Biology CH

Biology CH # 1 (english medium)

Science

Our universe operates under certain principles. For understanding of these principles, the experiments are done and observations are made; on the basis of which logical conclusions are drawn. Such a study is called "Science". In brief science is the knowledge based on experiments and observations.

Biology

The Scientific study of living organisms is called Biology. The word biology is derived from two Greek words "bios" meaning life and "logos" meaning thought, discourse, reasoning or study. It means that all aspects of life and every type of living organism are discussed in biology.

Branches of Biology

Biology is divided into following branches: Morphology

The study of form and structure of living organisms is called morphology. It can be further divided into following two parts: 1. The study of external parts of living organism is called external morphology. 2. The study of internal parts of living organism is called internal morphology or anatomy. Histology

the study of cells and tissues with the aid of the microscope is called Histology. Cell Biology

The study of structure and functions of cells and their organelles is called Cell Biology. Physiology

the study of different functions performed by different parts of living organism is called Physiology. Ecology

The study of organisms in relation to each other and their environment is called Ecology or Environmental Biology.

Taxanomy

Living organisms are classified into groups and subgroups on the basis of similarities and differences. This is called classification Taxanomy is that branch of biology in which organisms are classified and given scientific names.

Embryology

The study of development of an organism from fertilized egg (zygote) is called embryology. The stage between zygote and newly hatched or born baby is called embryo. Genetics

The study of methods and principles of biological inheritance of characters from parents to their offspring is called genetics.

Paleontology

The body parts of ancient organisms or their impressions preserved in rocks are called fossils. The study of fossils is called paleontology. It also includes the study of origin and evolution of organisms. It can be divided into two parts: 1. The study of fossils of plants is called Palaeobotany. 2. The study of fossils of animals is called Palaeozoology. Biochemistry

The study of metabolic reactions taking place in living organisms is called biochemistry. These reactions may be constructive or destructive. The assimilation of food is a constructive process and respiration is a destructive process. Biotechnology

It is the branch of biology which deals with the practical application of organisms and their components for the welfare of human beings e.g. disinfections and preservations of food, preservations of insulin and biogas from bacteria etc.

Relationship of Biology with other Sciences

In ancient times, there was no distinction of biology and other sciences. Different fields of sciences like biology, chemistry, physics and mathematics are met together in the writings of ancient scientists. In ancient times, these subjects were studied under one head "science", but with the passage of time, the science developed very much and the huge scientific knowledge was then divided into different branches. However even today the interrelationship of these branches cannot be denied. Biophysics

The study of various biological phenomena according to principles of physics is called biophysics. For example, movement of muscles and bones based on principles of physics. Biochemistry

The study of different biochemical like carbohydrates, proteins and nucleic acids etc found in cells of living organisms and hundreds of the underlying chemical reactions in cells of organisms

is called biochemistry.

Biometry

The data obtained from observations and experiments on living organism is analyzed by various statistical methods. This is called Biometry. Biogeography

The study of plants and animals and the basis of geographical distribution is called Biogeography. Bio-Economics

The study of living organisms from economic point of view is called Bio-Economics. It includes the study of cost effectiveness and viability of biological projects from commercial point of view.

Biological Method of Study or Method Used to Solve the Problem of Malaria

Observation

Most of the biological investigations start with an observation. After selecting, specific biological problem, observations are made to collect relevant information. For example; take the case of Malaria. Malaria is the greatest killer disease of man for centuries. Malaria was one among many other diseases for which a cure was needed. In 1878, A French physician, Laveran, studied the blood sample of Malaria patient under microscope and observed tiny creatures in it. These creatures were later called Plasmodium. Hypothesis

To solve a scientific problem, one or more possible propositions are made on the basis of the observations. Such a proposition is called a Hypothesis. The hypothesis is tested by scientific method. Merits

A good hypothesis has the following merits: 1. It is close to the observed fact. 2. One or more deductions can be made from this. 3. These deductions should be confirmed doing experiments. 4. Results whether positive or negative should be reproducible. To know the cause of malaria, following hypothesis was made: Plasmodium is the cause of Malaria." Note: One or more than one possible deductions can be made from the hypothesis. Deduction

the logical conclusion drawn from a hypothesis is called deduction. Testing one deduction and finding it correct does not necessarily mean the hypothesis is correct and scientific problem is solved. Actually, if more deductions are found to be correct; the hypothesis will be close to

solution of the problem. Experiments

Following groups are designed to perform experiments: Experimental Group It is the group of those people who are affected in some way and we do not know the real cause e.g. a group of malarial patients. Control Group It is the group of unaffected people e.g. persons group of healthy persons. By keeping both of these groups under similar conditions, the difference between them is determined. To know the real cause of malaria, the experts examined the blood of about 100 malarial patients (experimental group). On the other hand, the experts examined the blood of about 100 healthy persons (control group). Results

During the experiments mentioned above; the plasmodium was found in blood of most of malarial patients. The plasmodim was absent in the blood of healthy persons. These results verified the deductions and thus the hypothesis i.e. the plasmodium is the cause of Malaria, was proved to a considerable extent. Theory

If hypothesis is proved to be correct from repeated experiments and uniform results, then this hypothesis becomes a theory. Scientific Principle

When a theory is again and again proved to be correct, then it is called a scientific principle.

Contributions of Muslims Scientists in the Field of Biology

Many Muslim scientists contributed a lot in the field of biology but the following names are more respectable: Jabar-Bin-Hayan

Period: 722-817 A.D Books: Alnabatat and Alhaywan Contribution: He studied the life of plants and animals and wrote many books about them. Abdul-Malik-Asmal

Period:741 A.D Books: Al-Kheil, Al-Ibil, As-Sha, Al-Wahoosh, Khalaqul Insan. Contributions: He described the body structure and functions of horses, camels, sheep, wild animals and human beings in detail. Abu-Usman-Umer Al-Jahiz

Books: Al-Haywan Contribution: He explained the characteristics of about 350 species of animals. He wrote on the

life of aunts especially. Al-Farabi and Abu-ul-Qusim Al-Zahravi

Period: 870-950 A.D Books: Al-Nabatat, Al-Haywanat Contribution: The above mentioned books were written by Al-Farabi. On the other hand, Al-Zahravi was famous for removal of stone from urinary bladder. Ibn-ul-Haitham

Period: 965-1039 A.D Books: Al-Manazir, Mizan-ul-Hikma Contributions: Both of these books were famous and well known at that time. These books were translated into Latin, Hebrew, Greek and other western languages. He explained the structure and functions of eyes and suggested the cornea as a site of vision. Bu-Ali Sina

Period: 980 A.D Book: Al-Qanoon Fil Tib Al-Shifa Contribution: He wrote about plants, animals and non-living things in one book. He was expert in mathematics, astronomy, physics and paleontology. Ibn-ul-Nafees

Contribution: he described the blood circulation in the human body.

Ali Ibne Isa

Contribution: He worked on structure, functions of eye and about 130 diseases of eyes and their treatment.

Significance of Biology or Impact of Biological Study on Human Life

the present high level achievements of man are largely due to the advanced biological research. The study of biology is very important in routine matters of our life as described below. Food Production

Food has basic importance in our life. Due to researches in biology, there are great achievements in agriculture. For the production of cereal crops; the best varieties of seeds were selected. The yield of wheat corn, rice, sugarcane and cotton has been enormously increased bringing healthy effect and prosperity. Today, the man has overcome the problems of balanced diet, food storage and famine. Control on Diseases

Health is basic necessity of life. Due to researches in biology, the discovery of new antibiotics for many infectious diseases like plague, cholera, pneumonia, tuberculosis and typhoid has made the life easy. The infant mortality has reduced due to discovery of vaccines for fatal diseases like

small pox, polio, tetanus and diphtheria. Today AIDS is problem for world. The germs of this disease destroy the natural resistance and immunities against diseases. A medicine called AZT has been found effective for AIDS. Similarly many drugs have been discovered for treatment of cancer. Many organisms are used to produce drugs e.g. bacteria and fungi. We have controlled many infectious diseases by using drugs like penicillin and streptomycin. We have eliminated many harmful pests like locusts, flour beetle, termites, fungi, shipworm etc by using pesticides. Genetic Engineering

Genetic engineering is a technology in which useful genes are inserted into the bacteria etc, to get required beneficial results. Using this technique, manipulation of heredity material is done and new species are produced e.g. Doli sheep. Today human insulin gene is inserted into DNA of bacteria to synthesize insulin on commercial bases. This insulin is found to be very useful in treatment of diabetic patients.

Pollution Control

Due to increasing urbanization, industrialization and automobiles, the man and other organisms have to face a great danger, "the environmental pollution". due to pollution of air, land and water there is danger to humans aid wild life. Many plants and animals have been maintaining the balance in our environment for millions of years and now at the verge of extinction due to pollution. By biological research, scientists are busy to find out causes and ways to control the pollution. The biology thus, has greatly improved the quality of our life. Space Biology

On Mars, some evidence of life has been found which is still under further investigation. During exploration of space the scientists have been conducted experiments on different plants, animals, fungi and bacteria in space and they have obtained very useful information.

Islamic concepts About Origin of Life

We have got much information about origin of life by studying the Holy Quran.

Ultimate Creator

The first thing learnt from teachings of Quran is that Allah is the ultimate creator of everything whether plants, animals or non-living things. "Allah is the creator of all things and He is Guardian of overall things." - (Surah Zamar-Ayat 62) Not only plants, animals and non-living things and human beings but also the heavens and whole universe have been created by Allah. Origin of Life from Water

The second important fact we get from Quran is that Allah has created all living thins from water.

"We made every thing from water." - (Sura Ambia - Ayat 30) Viruses, bacteria, algae, fungi, different plants, all animals and humans are all living things. According to Quranic verses, all diverse living things were created from water. Common Origin

From above mentioned sayings of God there is an indication for common origin of living things or we can at least say that all living things have come out from water. Creation of Man

Allah also sys in Quran: "He created man from clay like the potter's." - (Sura Rehman - Ayat 14) It seems that there were following two sages for creation of man: 1. Creation from water. 2. The first created thing, on admixing with clay was transformed into more advanced beings. The same can also be applied to other animals because there are certain similarities between structure of man and other animals. In vertebrate animals, the structures of digestive system, respiratory system, blood circulatory system, excretory system and reproductive system etc are similar to great extent, although differ in other details. Reproduction in living things. Once the life had been created, Allah implemented the process of reproduction for the continuity of races of animals and other organisms. The various stages of reproduction have been described in sura in following way: "Then fashioned we drop a clot, then fashioned we clot a little lump, then fashioned we the lump bones, then clothed the bones with flesh." - (Sura Almominoon Ayat 14) Classification and Evolution

"Allah has created every animal from water some of them creep up on their bellies, other walk on two legs, and others on four, Allah creates what the pleases. He has power overall thins." - (Sura Nur Ayat 45) "Hath there come upon man (every) any period of time in which he was a thing unrememberd?" - (Sura Dahar Ayat 1) The close study of above sayings of God reveals that all animals had a common origin but they gradually underwent changes after words and became different from each other i.e. some animals became crawler, some bipedal and some other tetra pods. The present animals are advanced forms of the past animals who achieved this form after passing through many changes.

Concept of Abiogenesis and Biogenesis for Origin of Life on Planet Earth

Scientific Views About Origin of Life

How did life originate on this earth? This may never be know for certain to science because neither it is possible today to make observation of primitive events when the life actually originated nor there is any fossil record of first formed soft bodied organisms. However, in 1950 some scientists created the primitive earth condition (approximately 4 billion years ago) in the laboratory and performed experiments. On the basis of results obtained from these experiments, scientists formulated some ideas. These ideas seem to be close to reality. Abiogenesis and Biogenesis

In ancient times, there were two views about the origin of life: 1. According to one view, offspring are produced from their parents by process of reproduction, this is called concept of Biogenesis. 2. According to other view, living things are produced spontaneously from non-living things. This is called concept of Abiogenesis. Because at that time, there was neither so much advancement in science nor scientific tools like microscope and other instruments were invented, which could help in detailed observations about reality. According to some people, insects are produced from dewdrops, rats from debris, frogs from mud, and maggots from putrefied meat. Some scientists like Copernieus, Bacon, Galileo, Harvey, and Descartes also believed this concept. From 16th to 18th century many scientists performed experiments to test this concept. They found some animals to be developed from non living matter. Therefore this concept seemed to be correct. Later on, scientists performed experiments with more care. First of all an Italian scientists, Francesco Redi, (1668) proved that this concept was wrong.

Redi's Experiment

Redi took four bottles. He put a dead snake in one bottle, a few dead fish in second bottle, dead eel in third bottle and a piece of meat in the fourth bottle. All these bottles were left open. The flies could enter these bottles. Then he took four more such bottles. He put some dead animals in all four bottles but covered the mouth of bottles. (Figure from book) After few days, maggots were produced in four open bottles. Maggots were not produced in closed bottles. Moreover, no flies were seen. Therefore, it was proved that maggots were not produced spontaneously by produced due to flied which were visiting the open bottles. The maggots were the larvae produced from the eggs of the visiting flies.

Needham's Experiment

In 1948, an English scientist Needham boiled the meat in the water and prepared gravy. He poured this gravy into the bottles and closes their mouth with corks. After some days, many microscopic organisms were produced. In this way, the believers of abiogenesis were once again gain courage. (Figure from book)

Experiment of Spallanzani

In 1767, an Italian scientists Spallanzani criticized the experiment of Needham. He said that air entered the bottles through the pores of cork and hence living organisms were produced. (Figure from Book) Spallanzani put the boiled meat and vegetables in clean bottles and then sealed the mouth of bottles by heat. He placed these sealed bottles in boiled water to kill the possible germs. After some days, he found no organisms. He left the same boiled meat and vegetables in open bottles

at the same time. Some living organisms were produced in these bottles. This supportd the concept of Biogenesis. But the believers of Abiogenesis said that air removed by Spallanzani was necessary for living things so no organisms were produced in sealed bottles. When oxygen was discovered the supporters of Abiogenesis said that Spallanzani had removed oxygen where by no life could be produced in his experiment.

Experiment of Louis Pasteur

The argument on Biogenesis and Abiogenesis continued up to the middle of, 19th century. A well-known French scientist, Louis Pasteur proved, after simple but very careful experiments, that abiogenesis could not occur in present environment of earth. He proved that living organisms could only be produced from their parents. In 1864, Pasteur performed his experiment in front of the commission formed to solve the issue. He took flasks, which had long curved S-shaped necks. He placed fermentable infusion (Yeast + sugar + water) in flasks and left their mouth open. (Figure from Book) He boiled the yeast infusion in the flasks. After this, he allowed to cool them and kept them as such. He observed that no life ws produced even after the lapse of several days, because microscopic organisms entering along with air got stuck up in on the curved walls of the glass necks. Then he broke up the curved necks, so that air containing microscopic organisms could reach the infusion. Now he noted that microscopic organisms were produced within 48 hours. This proved that if care was taken and no microscopic organisms and reproductive structures (eggs or spores) approach the infusion, no life could be produced because thee is no spontaneous generation of life from non life. After Pasteur, no further experiments were performed on origin of life for the next 60 years. In 1920, a Russian biochemist Alexander Oparin and a British biologist J.B.S 1-Ialdane suggested that life on earth was originated after a long and gradual molecular evolution and there was no spontaneous and miraculous origin of life on earth.

[Chemical and Organic Evolution of Life on Earth

The modern view of the origin of life stresses on the idea of chemical evolution. According to Oparin and Haldane, the origin of first life had been initiated from the time of the existence of the solar system (the sun with its nine planets). The earth, like the sun was made up of light and heavy elements. Heavy elements like iron, nickel etc were present in the nucleus of the earth, while the light elements and compounds like hydrogen, methane, nitrogen, carbon, ammonia, nitrogen oxide, etc in the form of vapours existed on the surface of the earth. These light elements and compounds were responsible for the first life on earth. The earth had high temperature and radiation and had frequent and abundant discharges. In these conditions, the first life originated. Oparin and Haldane suggested that simple inorganic molecules slowly and gradually combined to produce complex organic molecules from which the simplest form of life (bacteria) came into existence. This process took a long time. Haldane proposed that primitive earth's atmosphere had only carbon dioxide, ammonia and water vapours. If a mixture of these gases is exposed to ultraviolet radiation, it leads to the formation of organic compounds like sugar and amino acids. As free oxygen was not available to check the

radiation from reaching the earth so substances like sugar and amino acids went on accumulating under such conditions. About 15 billion years ago, there was a huge explosion (Big Bag). The universe started expanding and the temperature dropped drastically. In time, about 4.6 billion years ago our earth and other planets appeared as part of the solar system. The primitive atmosphere of the earth was rich in hydrogen. With the passage of time, the atmospheric temperature gradually dropped. This allowed condensation and heavy rains, which caused formation of oceans. Thunder and lightning sparks together with ultraviolet radiation caused reactions of the atmospheric gases resulting in the formation of simple organic molecules. These molecules came down with the rains and accumulated in the seas, oceans, lakes, rivers and the soil over a very long period of time. These molecules interacted and produced amino acids and proteins which are the body building substances. The fossil evidence indicates that the earliest forms of organisms lived about 3.8 billion years ago. From this it is speculated that the origin of life started about 4 billion years ago. The earliest organisms were heterotrophs. The depletion of the pre-existed food from the environment led to the evolution of organisms capable of making their own food. They became autotrophs, and added free oxygen into the atmosphere. For at least the first 2 billion years of life on earth, all organisms were bacteria. About 1.5 billions years ago, the first eukaryotes appeared. The idea of organic evolution was supported by scientists like Lamarck and Charles Darwin.

Differentiate between Biogenesis and Abiogenesis

Biogenesis A theory which describes the origin of life on the earth from pre-existing living

organisms is called Biogenesis.

It was based on practical experiments and material evidence.

It was supported by the experiments performed by Redi and Pasteur.

It was based on practical basis.

It describes the process of reproduction as an essential ability of living organisms.

Abiogenesis A theory which describes the origin of life on the earth from non living things is called

Abiogenesis.

It was based on observations and national thoughts.

It was supported by the fungus of bread: and production of frogs in the mud.

It was based on theoretical basis.

It gives no scientific reasoning about the production of life.

Differentiate between Hypothesis and Theory

Hypothesis The process of making some possible answers for the related biological problem is called

Hypothesis.

It is the step of biological methods which gives the way to carry on the research.

Hypothesis is an uncertain intelligent statement.

Hypothesis is formed from observations and collected facts.

Theory The final explanation which is given on the basis of hypothesis and deduction if they are

found correct is called theory.

It is the step of biological method which gives actual reason to biological method.

Theory is certain intelligent statement.

Theory is formed by experimentation, physical evidence to explain the laws of nature

Chemistry

The branch of science which deals with the composition and properties of matter, changes in matter and the laws or principles which govern these changes is called Chemistry.Branches of ChemistryPhysical Chemistry

The branch of chemistry which deals with the physical properties and physical behavior of material things is called physical chemistry.Inorganic Chemistry

The study of all elements and their compounds except carbon is called inorganic chemistry.Organic Chemistry

The branch of chemistry in which we study the compounds of carbon is called organic chemistry.Analytical Chemistry

The branch of chemistry which discusses the analytical methods for getting information about chemical compounds and chemical processes is called analytical chemistry.Biochemistry

The study of chemical compounds present in living things is called biochemistry.Industrial Chemistry

The application of chemical knowledge in technology and industry and the preparation of industrial products are called industrial chemistry.

Steps Involved in Getting Information in the Scientific Method

Science is not only an integrated knowledge of physical and biological phenomena but also the methodology through which this knowledge is gathered. The process of scientific discoveries is a cyclic process.

In science the facts are gathered through observations and experiments and then theories or law are deduced. The scientific method include following four steps:

1. Observation

2. Inference

3. Prediction

4. ExperimentObservation

The observations are made by the five senses of man. Men made equipments are also used for making observations. For example microscope is used for observing minute objects. Thermometer is used to measure temperature. Sensitive balance is used to determine the mass of a very light object. The capacity of man made instruments is also limited. But it can be improved by improving technology. Thus better and more reliable information are given to the scientists who produce better result. Information acquired through careful observations are called facts. These facts are foundation of scientific knowledge.Inference

The facts gathered through observations are carefully arranged and properly classified. Correlating the knowledge thus acquired with previous knowledge, we try to think of a tentative solution to explain the observed phenomenon. The tentative solution is called hypothesis. The validity of this hypothesis is tested through the results obtained from experiments. The results are discussed by the scientists and the hypothesis is accepted or rejected. The accepted hypothesis then takes the form of theory. A theory when repeatedly gives the same results after experimentation and gives correct explanation of the scientific facts becomes a law or principle.

A theory remains valid until contrary informations are given on the basis of experimentation. Thus a hypothesis requires experimental support. But Avogadro's hypothesis has been accepted as law without any experimental support.Prediction

Facts, theories and laws which are deduced from observation can help in deducing more facts and phenomenon. This process is called prediction.Experiment

An experiment is an integrated activity, which is performed under suitable conditions with specially designed instruments to get the required information. Such information is used to test the validity of the hypothesis. If a hypothesis is proved correct. It increases the reliability of known facts. If it is proved wrong, it stil can give information which can be used to deduce other results.

Chemistry and Society

Chemistry has played important role for well being of mankind in the form of food, clothing, shelter, medical treatment and chemical fertilizers, crops protected by insecticides, refined food and production of artificial fiber. Production of cement, iron bricks, glass, paint etc are all due to chemistry.

The hazards of chemistry are so vast that no aspect of human life has remained unaffected. The smoke coming from chimneys of chemial industries and from vehicles pollute the air. It is very dangerous to breath in that air. Similarly waste water from industry, pollute canals, rivers and has bad effect on land. Excessive chemical spray on plants also has bad effect.

Chemical Combinations and Chemical Equation 9th ClassChemistry Notes « on: July 02, 2010, 06:41:44 PM »

2. Law of Definite Proportions

3. Law of Multiple Proportions

4. Law Reciprocal Proportions

Antoine Lavoiser has rejected the worn out ideas about the changes that take place during a chemical reaction. He made careful quantitative measurements in chemical reactions and established that mass is neither created nor nor destroyed in a chemical change.

Law of Conservation of MassStatement

It is presented by Lavoiser. It is defined as:

"Mass is neither created nor destroyed during a chemical reaction but it only changes from one form to another form."

http://www.ysapak.com/YSAforum/index.php/topic,848.msg1274.html#msg1274

In a chemical reaction, reactants are converted to products. But the total mass of the reactants and products remains the same. The following experiment easily proves law of conservation of mass.Practical Verification (Landolt Experiment)

German chemist H. Landolt, studied about fifteen different chemical reactions with a great skill, to test the validity of the law of conservation of mass. For this, he took H.shaped tube and filled the two limbs A and B, with silver nitrate (AgNO3) in limb A and Hydrochloric Acid (HCl) in limb B. The tube was sealed so that material could not escape outside. The tube was weighed initially in a vertical position so that the solution should not intermix with each other. The reactant were mixed by inverting and shaking the tube. The tube was weighed after mixing (on the formation of white precipitate of AgCl). He observed that weight remains same.

HCl + AgNO3 ----------> AgCl + NaNO3

Law of Definite ProportionsStatement

It is presented by Proust. It is defined as:

"When different elements combine to give a pure compound, the ratio between the masses of these elements will always remain the same."

Proust proved experimentally that compound obtained from difference source will always contain same elements combined together in fixed proportions.Example

Water can be obtained from different sources such as river, ocean, well, canal, tube well, rain or by the chemical combination of hydrogen and oxygen. If different samples of water are analyzed, it will have two elements, hydrogen and oxygen and the ratio between their mass is 1:8.

Law of Multiple ProportionsStatement

This law is defined as:

"When two elements combine to give more than one compounds, the different masses of one element, which will combine with the fixed mass of other element, will be in simple whole number ratio."

Two different elements can combine to form more than one compound. They can do so by combining in different ratios to give different compounds.

Example

Hydrogen and oxygen combine with one another to form water (H2O) and hydrogen peroxide (H2O2). In water and hydrogen oxide 2 g of hydrogen combine with 16g and 32g of oxygen respectively. According to law of multiple proportions, the different masses of oxygen (16g and 32g) which have reacted with fixed mass (2g) of hydrogen will have a simple ratio between each other i.e. 16:32 or 1:2. It means that hydrogen peroxide contains double the number of oxygen atoms than water. This law proves this point of Dalton's Atomic Theory that atoms do not break in a chemical reaction.

Law of Reciprocal ProportionsStatement

This law is defined as:

"When two element A, B combine separately, with the mixed mass of the third element E, the ratio in which these elements combine with E is either the same or simple multiple of the ratio in which A and B combine with each other."Example

Hydrogen and Nitrogen separately combine to form ammonia (NH3) and dinitrogen oxide (N2O), in these compounds, fixed mass of nitrogen is 14g and combines with 8 g of oxygen and 3 g of hydrogen. The ratio between the mass of oxygen and hydrogen is 8:3. Hydrogen and oxygen also combine with one another to form water (H2O). The ratio between hydrogen and oxygen in water is 16:2. These ratios are not same. Let us observe whether these ratios are simple multiple to each other or not following mathematical operation is carried out.

8:3 ::16:2

8/3 : 16/2

or

8/3 x 2/16

or

1/3 => 1:3

DefinitionsAtomic Mass

The mass of an atom of the element relative to the mass of some reference or standard element is called atomic mass. Atoms are very small particles. They have very small mass. If the masses of atoms were to be expressed in gram. It is a very big unit for this very tiny object. Then it was

decided by the chemists that masses of the atoms were to be found after comparing with mass to some standard form.

Hydrogen being the lightest element is taken as standard. The mass of the hydrogen atom taken as one.

The atomic mass could be defined as

"Atomic mass of an element is the mass of an atom of that element as compared to the mass of an atom of hydrogen taken as one."Example

The atomic mass of sodium is 23. It means that an atom of sodium is 23 times heavier than hydrogen atom. Similarly atomic mass of oxygen is 16. It means that an atom of oxygen is 16 times heaviest than that of hydrogen.

Atom

The smallest particle of an element which cannot exist independently and take part in a chemical reaction is known as Atom.Examples

Hexogen(H), Carbon (C), Sodium (Na), Gold (Au) etc.

Molecule

The particle of a substance (Element or Compound) which can exist independently and show all the properties of that substance is called molecule.

Atoms of the same or different elements react with each other and form molecule.

Atoms of some elements can exist independently, since they have property of molecule so they are called mono atomic molecule.Examples

Examples of Molecules of the elements are Hydrogen (H2). Nitrogen (N2), Sulphur (S8) etc.

Molecules of different elements are called compounds. For example HCl, H2O, CH4 etc.

Valency

The combining capacity of all elements with other elements is called valency.Example

H = 1

C = 4

Al = 3

Mg = 2

Na = 1

Chemical Formula

"A brief name used for full chemical name at a compound is called Chemical Formula."

A chemical formula is used to represent an element or a compound in terms of symbols. It also represents the number and type of atoms of elements present in the smallest unit of that substance.Example

The chemical formula of hydrogen sulphide is H2S. It shows two types of elements (H and S) and number of atoms of element (2H and 1S). Similarly the formula of NaCl show number and type of different atoms present in its smallest unit.

Empirical Formula

"The formula which shows the minimum (simple) ratio between atoms present in a compound is known as Empirical Formula."Example

For example the empirical formula of hydrogen peroxide is HO that of water is H2O and benzene is CH.

Molecular Formula

The formula of an element or a compound which represents the actual number of atoms present in the molecule of these substances is called molecular formula.Example

Water, Hydrogen Peroxide, Ethylene Benzene and Sulphur have molecular formula H2O, H2O2, C2H4, C6H6 and S8 respectively.

Molecular Mass

Molecular mass of an element or a compound is defined as the mass of its molecule relative to 1/12th of the mass of C-12. It is the sum of the atomic masses of all the atoms presents in its molecular

formula.Example

Molecular mass of water (H2O) = 2 + 16 = 18 a.m.u

Mass of hydrogen sulphide (H2S) = 2 + 32 = 34 a.m.u

Formula Mass

Formula mass of a compound is the mass of its formula unit relative to 1/12th of the mass of C-12.Example

Formula mass of Sodium Chloride NaCl = 23 + 35.5 = 58.5 a.m.u

Formula mass of Calcium Chloride CaCl2 = 40 + 35.5x2 = 111a.m.u

Molar Mass

The mass of one mole of a substance is called molar mass.Example

1 mole of Hydrogen atom (H) = 1.008g

1 mole of Hydrogen molecule (H2) = 2.016g

Thus mass of substance is related to the particles by mole.

Chemical Reaction

A chemical change in which reactants are converted to products is called chemical reaction.

Zn + 2HCl --------> ZnCl2 + H2

The fact that a chemical reaction is taking place can be inferred from the following observation.

1. Evolution of a gas

2. Change in colour

3. Change in temperature.

4. Emission of light.

Types of Chemical Reaction

The chemical reaction is classified into following types:1. Displacement Reaction

The reaction in which an atom or group of atoms is displaced by another atom or group of atoms in a compound is called displacement reaction.

Fe + CuO ---------> Cu + FeO2. Double Displacement Reactions

The reactions in which reacting substances exchange their radicals or ions are double displacement reaction. Insoluble salts are formed by mixing soluble salts.3. Addition Reactions

When two different compounds or elements react together to give only one confound, the reaction will be called addition reaction.

2Mg + O2 --------> 2MgO4. Decomposition Reaction

The reaction in which some compounds may decompose into elements or simpler compounds on heating is called decomposition reaction.

CaCO3 ---------> CaO + CO2 (Heat)

Chemical Equation

Symbolic representation of chemical change in terms of symbols and formulae is called Chemical Equation.Method of Equation Writing

A chemical equation can be written as follows:

1. Write the formulae and symbols of the reactants on the left hand side.

2. Write the formulae and sympols of the products on the right hand side.

3. Separate the reactants and products by an arrow which is directed towards the products.Characteristics of Chemical Equation

1. Chemical equation must be representative of a chemical reaction.

2. It should represent molar quantities.

3. It should be balanced in terms of atoms/molecules of reactants and products.

Reactants

Those substances, which react together in a chemical reaction, are called reactants.

Zn + 2HCl ------> ZnCl2 + H2

In the above reaction Zn and HCl are the reactants.Products

Those substances, which are formed in a chemical reaction, are called products.

Zn + 2HCl ------> ZnCl2 + H2

In the above reaction, ZnCl2 and H2 are products.Information obtained from a Chemical Equation

1. A balanced equation indicates that which reactant undergo chemical change. It indicates that which products are formed.

2. It indicates that how many moles of reactants under go chemical change. It indicates that how many moles of products are formed.Why are Chemical Equations Balanced

A chemical equation must be balanced in order to satisfy the law of conservation of matter, which states that matter can neither be created nor be destroyed during a chemical reaction.

« on: July 02, 2010, 06:41:05 PM »

Group

The vertical column of elements in the periodic table are called Groups.Period

The horizontal rows of elements in the periodic table are called Periods.Periodicity

The repetition of physical and chemical properties of elements periodically is called Periodicity of Properties.Periodic Law

Physical and chemical properties of elements are periodic function of their atomic masses.Metal

Elements which are good conductors of heat and electricity are malleable and ductile and have a

metallic luster are called Metals like Sodium, Potassium, Gold, Copper etc.Non-Metals

Elements which are non or bad conductor of heat and electricity are neither malleable or ductile and have no metallic luster are called Non-Metals like Carbon, Nitrogen, Chlorine etc.Metalloids

Metalloids are semi metals have the properties which are intermediate between a metal and non-metal like Boron, Silicon, Germanium, Arsenic, Antimony etc.

Law of Triads

A German Chemist, Dobereiner (1829), arranged chemically similar elements in groups of three on the basis of their atomic masses called Triads and it was found that atomic mass of the middle element was approximately equal to the average of atomic masses of other two elements. This is known as Law of Triads.Drawback or Defect

As very few elements could be arranged in such groups, this classification did not get wide acceptance.

Law of Octaves

An English Chemist Newland (1864) stated that if the elements were arranged in the ascending order of their atomic masses, every eight element will have similar properties to the first. This is knows as Law of Octaves.Drawback or Defects

1. Noble gases were not discovered at that time and no place was reserved for the undiscovered noble gases.

2. In the same way no blank spaces for the undiscovered elements were present in his table.

Mendeleyv's Period Table and Periodic Law

Russian Chemist, Mendeleyv's (186) who wa working separately from Lother Mayer published a table of elements.

According to Mendeleyv's when the element were arranged in order of their increasing atomic mases, the elements with similar properties were repeated after regular interval and were placed one above the other.A table obtained in this manner is called Periodic Table. Mendeleyv's stated this periodicity in the form of Periodic Law.

Important Features of Mendeleyv's Periodic Table

The important features of Mendeleyv's Periodic table are:Periods and Groups

The horizontal rows which run from left to right in Periodic Table are called Periods and they are twelve in number.

The vertical rows which run from top to bottom in periodic table are called groups and they are eight in number.Vacant Spaces

Mendeleyv's left many vacant spaces for the still unknown elements. For example, next to Calcium (40) should be Titanium (48) but it resembled silicon (28) instead of Aluminium (27). He left vacant space for element with atomic mass 44.Discovery of New Element

Mendeleyv's discovered new elements and also guessed their atomic mass and properties.Atomic Mass Correction

Mendeleyv's corrected the atomic masses of certain elements on basis of their properties and provided proper place to them in the periodic table.

Defects in Mendeleyv's Periodic Table

The Mendeleyv's Period Table has following defects:Irregular Position of Some Elements

According to Mendeleyv's Periodic Law Potassium (39) should be placed before Argon (40) but he placed Argon (40) before Potassium (39) which goes against his law.Position of Isotopes

Mendeleyv's periodic table gives no indication about the position of isotopes.Structure of Atom

Mendeleyv's Periodic table gives no idea about structure of atoms.Position of Lanthanides and Actinides

Lanthanides and Actinides have not been given proper place in Periodic Table.Coinage and Alkali Metals

Alkali metals and coinage metals with different properties are placed in the same group. This

defect has been replaced by placing them into two sub groups.

Modern Periodic Law and Modern Periodic TableModern Periodic Law

Physical and chemical properties of the elements are periodic function of their atomic number. Mosely (1913) says that atomic mas is not fundamental property. Due to some defects present in Mendeleyv's periodic law, Mosely introduced the concept of anomic number for the elements.Example

When isotopes were discovered, it was thought advisable to arrange the elements on basis of their atomic number instead o increasing atomic mases. Isotopes were needed different position in the Mendeleyv's periodic table. Hence Mendeleyv's periodic law was modified.

Modern Periodic Table

When Mendeleyv's periodic law was modified and new elements were discovered. This forcd the scientists to change Mendeleyv's periodic law.

The electronic configuration of atoms also played an important role in he arrangement of the modern periodic law. This form of periodic table is called "Long form of Periodic Table" because it contains eighteen groups instead of eight but seven periods instead of twelve.

Group I - The Alkali Metals

The elements of group I are called "Alkali Metals". The word alkali is derived from an Arabic word meaning Ashes.Elements of Group I

* Lithium

* Sodium

* Potassium

* Rubidium

* Cesium

* Francium

Properties of Group I

1. They are mono atomic.

2. They exist in solid metallic state.

3. Outer most shell of these elements is incomplete having one electron.

4. Elements of this group are highly reactive.

5. Elements of this group have large tendency to form compounds.

6. Elements of this group are strongly electro-positive.

Group II - The Alkaline Earth Metals

The elements of group II are called Alkaline Earth Metals. These elements occur in nature as silicate mineral and their oxides and hydroxides are strongly basic. Therefore these elements are called Alkaline Earth Metals.Elements of Group II

* Beryllium

* Magnesium

* Calcium

* Strontium

* Barium

* Radium

Properties of Group II


2. They exist in solid state.

3. Outer most shell of these elements is incomplete having two electrons.

4. Elements of this group are moderately reactive.

5. Elements of this group have moderate tendency to form compounds.

Group III - The Boron or Aluminium Family

The elements of group III exist in solid state.Elements of Group III

* Boron Metalloid

* Aluminium Metal

* Gallium Metal

* Indium Metal

* Thallium Metal

Properties of Group III



3. Outer most shell of these elements is incomplete having three electrons.

4. Elements of this group are quite reactive.


Group IV - The Carbon and Silicon FamilyElements of Group IV

* Carbon

* Silicon

* Germanium

* Tin

* Lead

Properties of Group IV



3. Outermost shell of these elements is incomplete.

4. Elements of this group are quite reactive.


Group V - The Nitrogen FamilyElements of Group V

* Nitrogen

* Phosphorus

* Arsenic

* Antimony

* Bismuth

Properties of Group V

1. Some are mono atomic and some are di-atomic.

2. Some of them exist in gaseous and some are in solid state.

3. Outermost shell of these elements is incomplete having five electrons.

4. elements of this group are quite reactive.

5. Elements of this group have quite tendency to form compound.

Group VI - The Oxygen FamilyElements of Group VI

* Oxygen

* Sulphur

* Selenium

* Tellurium

* Polonium

Properties of Group VI

1. Some are mono atomic and some are di-atomic.

2. Some of them exist in gaseous and some are in solid state.

3. Elements of this group have quite tendency to form compounds.

4. The tendency of forming covalent bond decreases from oxygen to polonium.

5. There is a gradual decrease in the ionization potential down the group.

Group VII - The Halogen FamilyElements of Group VII

* Fluorine Gas

* Chlorine Gas

* Bromine Liquid

* Iodine Solid

* Astatine Radioactive

Properties of Group VII

1. They are diatomic except At.

2. Halogens are very active non-metals.

3. Outer most shell of these elements is incomplete having seven electrons.

4. Elements of this group are highly reactive.

5. There is a gradual decrease in the ionization potential down the group.

Transition ElementsDefinition

Elements in Group IB, IIB, through VIIB are known as Transition Elements because they show their properties which are transitional between higly reactive and strong electro-positive elements of S-block which form ionic compounds and p-block elements which form largely covalent compounds.Properties of Transition Elements

1. Transition Elements have incomplete inner electron shells.

2. They show variable valency.

3. They show similar behaviour.

4. They all are metals.

5. They have strong inner atomic bonds.

Group 0, The Noble Gases

The elements of Group VIII A are called "Noble Gases" or "Inert Gases" or "Zero Group Elements".Elements of Group 0

* Helium

* Neon

* Argon

* Krypton

* Xenon

* Radon

Properties of Group 0


2. They exist in gaseous state.

3. Outer most shell of these elements is either complete or contains eight electrons.

4. These elements are mostly chemically non-reactive.

5. These elements have no tendency to form compounds (only a few of these compounds are known).

Atomic RadiusDefinition

One half of the distance between the nucleus of two identical atoms when these are in close contact with each other is called Atomic Radius.Unit

It is measured in angstrom unit A.Trend in Period

The atomic radii decreases from left to right within a period in the periodic table. This is because nuclear

charge increases with the increase of atomic number. But the number of shells remains same within a period.Trend in Group

Atomic radius increases from top to bottom in a group. This is because, although nuclear charge increases from top to bottom but at the same time on new shell is also added for each successive element down the group.

Ionization Energy (I.E) or Ionization Potential (I.P)Definition

The minimum energy needed to remove an electron from an isolated, gaseous atom in its ground state is called Ionization Energy.Unit

It is expressed in electron volts or kilo-joules permole.

1 ev = 96.49kjFactors Affecting Ionization Energy

The ionization energy of elements depends upon the following factors:1. Effect of Nuclear Charge on I.E

The greater the nuclear charge the higher is the ionization energy.2. Effect of Atomic Size

The larger the size of atom the lower is the ionization energy.Trend of I.E in Period

Ionization energy increases from left to right in a period due to increase in nuclear change and decrease in atomic size.Trend of I.E in Group

I.E decreases from top to bottom in a group due to increase in atomic size.

ElectronegativityDefinition

The tendency of each atom in a covalent molecule to attract a shared pair of electrons towards itself is known as its electronegativity.Factors Affecting Electronegativity

Electronegativity depends upon the following factors:

* Atomic size

* Atomic Number

* Electron Affinity

* Ionization Energy

Trend or Variation in the Period

Electronegativity increases from left to right within a period due to increase in nuclear charge and decrease in atomic size.Trend or Variation in the Group

Electronegativity values decreases from top to bottom within a group due to increase in atomic size.

Electron AffinityDefinition

The energy change that occurs when an electron is gained by an atom in the gaseous state is known as Electron Affinity.

Electron Affinity for the addition of first electron is negative i.e. energy is released but for further addition of electrons it is positive because energy has to be added to over come repulsion between negative ion and electron.Unit

It is measured in KJ/mol or in e.v per atom.Factors Affecting Electron Affinity

* Atomic Size

* Nuclear Charge

Tend or Variation of Electron Affinity in Group

Down the group in the periodic table, electron affinity decreases because the addition of a new shell to each atom decreases its force of attraction.Trend or Variation of Electron Affinity in Period

In a period, the electron affinity increases from left to right because the incoming successive atoms have higher nuclear charge and attract electron more towards itself.« on: July 02, 2010, 06:40:25 PM »

States of Matter

Matter has three states: 1. Gas

2. Liquid 3. solid These are physical states of matter. The three states of one matter may have different physical properties while their chemical properties are same. Water exists in three physical states solid (ice), liquid and gas(steam) has same chemical properties.

Kinetic Theory of Matter

The Kinetic theory was presented to explain the properties of gases and is called kinetic theory of gases. But this theory was also able to explain the composition of liquid and solid state of matter. So its is called Kinetic Theory of Matter. According to Kinetic Theory of matter: 1. All matter is composed of atoms, molecules or ions. 2. These particles have kinetic energy due to which they are in the state of motion. 3. In gaseous state, these particles move in a straight line. They collide with one another and with the walls of container. In liquids the rate of their movement is very small but in solids, there is to and fro motion only. 4. Generally material particles can have three types of movements, i.e. translational, rotational and vibrational. @import "/extensions/GoogleAdSense/GoogleAdSense.css";

Solids

The state of matter which has definite shape and volume is called solid. Properties of Solids

1. Definite Volume and Shape

The cohesive forces in solid substances are so strong that they keep their particles arranged in fixed positions. So due to restrict movements of particles, the solids have definite volume and shape. 2.Motion of Particles

The solid particles have vibrational motion only because these particles are held in fixed position by strong cohesive forces. 3. Effect of Heat

The physical state of solid substance can be changed by heating. On heating solid is converted to liquid and gaseous state. Heat increases the kinetic energy of the particles and they start vibrating at higher frequency. At a particular temperature the vibrational motions become fast that they overcome the cohesive forces and solid melts to liquid. 4. Melting Point

The temperature at which the solid is converted to liquid on heating is called melting point. At melting point, the particles of solid loose their means position and their arrangement. The solid

collapses and turns to liquid. 5. Sublimation

The conversion of some solids directly into gaseous state on heating is called sublimation. Iodine, ammonium chloride and naphthalene change directly into vapour state upon heating.

Liquid

The state of matter having definite volume but indefinite shape is called liquid. Properties of Liquid

1. Volume

Liquids have definite volume. In liquid particles are very close to one another and have cohesive forces among the particles. Due to the presence of cohesive forces, liquids have definite volume and keep their level as well. 2. Shape

Liquids do not have any specific shape. They adopt the shape of the container. The molecules of liquid are able to move. Due to this random motion the molecules of liquid do not have fixed position and as a result, a liquid does not have any specific shape. 3. Evaporation

Conversion of liquid into its vapours at any temperature is called evaporation. The molecules of liquid come to the surface of liquid and escape by overcoming cohesive forces. So liquid is converted to vapours at all temperature. 4. Boiling Point

The temperature of a liquid at which its vapour pressure becomes equal to the atmospheric pressure is called boiling point. @import "/extensions/GoogleAdSense/GoogleAdSense.css";

Gas

The state of matter which does not have definite shape and volume is called gaseous state. Properties of Gaseous State

1. Indefinite Volume and Shape

In gaseous state, the molecules have insignificant cohesive forces among themselves. They move very fast in all possible directions. As a result, a gas neither has fixed shape nor a fixed volume. 2. Kinetic Energy of the Particle of a Gas

Gas particles have very high kinetic energy as compared to liquid and solid state. 3. Pressure

The molecules of a gas are in the state of random motion. The molecules of gas not only collide with one another but also with the walls of the container in which they are enclosed. Due to their collision, the velocity of the molecules changes every moment. The pressure exerted by gas is also due to the collision of its molecules with the walls of the container. 4. Elastic Collision

The collision of gas molecules is elastic in nature which means that the total energy of the colliding molecules remains the same before and after the collision. 5. Kinetic Energy

The kinetic energy of molecules of gas is very high as compared with solid and liquid.

Diffusion

The movement of molecules from a higher concentration to a lower concentration is known as Diffusion. If the concentration of molecules at a particular place is higher, they start moving towards a place where their concentration is lower. When the concentration of molecules at both the places becomes equal the process of diffusion stops. Diffusion in Gases

The molecules of one gas can diffuse easily into the molecules of other gas. For example if an open bottle of a perfume is kept in a room, its smell will spread uniformly throughout the room. The liquid perfume present in the bottle volatilized slowly and its vapours diffuse through out the room. Graham's Law of Diffusion

Scottish Chemist, Thomas Graham (1833) discovered that lighter gs can diffuse through porous pot faster than the heavier one. This is called Graham's Law of Diffusion. Hydrogen being lighter gas will diffuse faster than oxygen or carbon dioxide. Diffusion in Liquids

Liquid molecules can also diffuse because they have free movement. Since the molecules of liquid move comparatively slowly than gas molecule, their rate of diffusion are also lesser than gases.

Brownian Movement

Robert Brown (1927) discovered this phenomenon: The free movement of the molecules of gases and liquid is called Brownian Movement." When a pollen grain is put in water. The movement of pollen grain in water is observed by microscope. It is observed that pollen grain is continuously moving in all directions. This free movement of pollen grain was due to the free movement of water molecules. The colliding water

molecules will also force pollen grain to move as well. The students can observe Brownian movement with the help of simple experiment. Experiment

Put a drop of milk on a microscope slide and cover it with cover slip. Put it under microscope and observe it. You will see small particle of fat moving randomly in milk. The movement of fat particles is actually due to the movement of water molecules in milk

Solution and Suspension 9th ClassChem



istry Notes « on: July 02, 2010, 06:39:50 PM »

Solution



A homogeneous mixture of different chemical substances which has uniform chemical composition through out and shows uniform physical properties is called solution. For example dissolve a small amount of copper sulphate in water the water will become blue. If this blue liquid is filtered, it will pass through the filter paper without leaving any solid. The mixture thus prepared is called a solution.

Binary Solution

A solution which is formed by mixing two substances is called binary solution. For example solution of glucose and water.

Solute

The component of a binary solution which is in lesser amount is called solute. For example in copper sulphate solution, copper sulphate is solute.

Solvent

The component of a binary solution which is in greater amount is called solvent. For example in copper sulphate solution, water is solvent.

Saturated solution

A solution in which maximum amount of a solute has been dissolved at a particular temperature and in which the dissolved form of solute is at equilibrium with its undissolved form is called saturated solution.

Unsaturated Solution

Solution which can dissolve further amount of a solute at a [particular temperature is called an unsaturated solution.

Supersaturated Solution

The solution which contains even more amount of solute required to prepare saturated solution is called super saturated solution. The hot saturated solution of compound like sodium thiosulphate does not crystallize its solute if cooled slowly without disturbance. Such a solution is called supersaturated solution. @import "/extensions/GoogleAdSense/GoogleAdSense.css";

Dilute Solution

A solution which contains small amount of a solute as compared to the solvent is called dilute solution.

Concentrated Solution

A solution which contains excess amount of a solute as compared to that of a solvent is called a concentrated solution.

Concentrated Solution

The amount of solute present in given quantity of solvent is called concentration of solution. The concentration of a solution can be expressed in many ways depending upon the amount o solute and solvent present in it.

Concentration of Solution

The amount of solute present in given quantity of solvent is called concentration of solution. The concentration of a solution can be expressed in many ways depending upon the amount of solute and solvent present in it. Percentage by Mass

The percentage of solute by mass is the mass of solute present in hundred part of the solution. For example 5% hydrogen peroxide solution by mass means that 5g hydrogen peroxide are dissolved in 95g of water to give 100g of solution. Percentage of Mass = (Mass of Solute/Mass of Solution) x 100 Percentage by Volume

The concentration unit expresses the volume of solute present in 100cm3 of solution. For example 15% solution of alcohol by volume will mean that 15cm3 alcohols are present in 100cm3 of solution. (Here 3 represents cube) Percentage by Volume = (Volume of Solute/Volume of Solution) x 100 Molar Solution

The solution that contains one mole of solute in 1dm3 of solution is called a molar solution. The concentration of this solution is expressed as M. Molarity

Molarity of a solution is the number of moles of solute present in 1dm3 of the solution. It is expressed as M. M = Number of Moles of Solute/Volume of Solution in dm3

or M = (Mass of solute/Molecular Mass) x (1/ Volume of Solution in dm3)

Crystallization

The process in which crystal separates from saturated solution on cooling is called crystallization. It is a useful process because it can be used to purify the impure solid compounds. It can also be used to separate a mixture of solids.

Hydration

The ions surrounded by solvent molecules in solution are called solvated ions. If water is a solvent these ions are called hydrated ions.

Suspension

A suspension in such a mixture in which solute particles do not dissolved in solvent and if filtrated its particles do not pass through the pores of filter paper.

Colloidal Solution

In a colloidal solution the solute particles are slightly bigger than those present in a true solution but not big enough to seen with naked eye.

Standard Solution

A solution whose molarity (strength) is known is called Standard Solution.

True Solution

A True Solution is such a mixture in which solute particles are completely homogenized in the solvent for example solution of sodium chloride or copper sulphate in water. @import "/extensions/GoogleAdSense/GoogleAdSense.css";

Solubility

Solubility o a solute in a particular solvent is defined as the amount of solute in grams, which can dissolve in 100g of the solvent at a particular temperature to give a saturated solution. or The amount of a solute in gram moles, which can dissolve in one kilogram of the solvent at a

particular temperature, to give a saturated solution. Factors Affecting the Solubility

Effect of Solvent

Similar solvents dissolve similar solutes, i.e. if the chemical structure and the electrical properties such as dipole moment of solute and solvent are similar, the solubility will increase. If there is dissimilarity in properties, then either the solute will not dissolve or there will be very little solubility. Effect of Solute

Different solutes have different solubility's in a particular solvent e.g. if the saturated solutions of table sugar and sodium chloride are prepared, it is found that the concentration of sodium chloride solution is 5.3 molar while that of sugar solution is 3.8 molar. In other words, the solubility of sodium chloride in water is far greater than that of sugar. This is due to the fact that the attraction of sodium (Na+ and chloride (Cl-) ions with water is greater than that of sugar molecules with water. Effect of Temperature

Change in temperature has different effects on the solubility of different compounds. Usually the solubility increase with the increase in temperature but it cannot be taken as a general rule. The solubility of compounds like lithium carbonate, calcium chromate decreases with the increase in temperature. The solubility of gases in water also decreases with the increase in temperature. On the other hand, there are a large number of compounds whose solubility in water increase with the increase in temperature e.g. sodium nitrate, silver nitrate, Potassium chloride etc. the solubility of sodium chloride in water does not increase appreciably with the increase in temperature

Electro-Chemistry 9th ClassChemistry Notes « on: July 02, 2010, 06:39:16 PM »

Electro-Chemistry

The branch of chemistry which deals with the study of chemical energy to electrical energy or electrical energy to chemical energy is called electro-chemistry.

Conductors

Those substances through which electric current can pass are called conductors. For example all metals are conductors.

Non-Conductors



Those substances through which electric current cannot pass are called non-conductors. For example plastic, wood are non-conductors.

Electrolysis

The process in which electricity passes through the aqueous or infused state of some substance. The substances itself decompose into its component. This process is called electrolysis.

Electrolyte

The compound in molten state or in aqueous solution through which electricity can pass are called electrolyte.

Non-Electrolyte

Those compounds through which electricity cannot pass are called non-electrolyte.

Strong Electrolyte

The substances which are highly soluble and completely ionized are called strong electrolyte. For example acids, bases and salts are strong electrolytes.

Weak Electrolyte

The substances which are not highly soluble and remain in un-ionized form are called weak electrolyte. @import "/extensions/GoogleAdSense/GoogleAdSense.css";

Electroplating

A process in which metal is deposited on the surface of another metal by electrolysis is called electroplating.

Objectives of Electroplating

Decoration

It is done for decoration. Noble and precious metals like gold or silver are deposited on the inferior metals to enhance their beauty and look beautiful. Protection

Electroplating is done to protect the metals from rusting as well as from attack of other substance like organic acids and acidic gases. Repair

It can be used to repair the broken machinery by electroplating with other metals. Usually the metals like copper, silver, chromium, nickel and gold are used for electroplating.

Procedure of Electroplating

The metal which is to be electroplated is first cleaned with sand and then washed with caustic soda solution and finally with a lot of water. This metal is made cathode and the metal which is going to be deposited is made anode. The electrolyte is a salt of metal being deposited and electroplating is carried out in a tank made of cement, glass or wood. It is called an electrolytic tank. The electrolyte should have following properties: 1. It must be very soluble in water. 2. It must be good conductor. 3. Cheap 4. May not easily oxidized or reduced or hydrolyzed. (Diagram)

« on: July 02, 2010, 06:38:43 PM »

Metals and Non Metals

Metals

1. Metals have luster shine surface. 2. Metals reflect heat and light. 3. Metals conduct heat and electricity 4. Metals are ductile and can be drawn into wire. Non-Metals

1. Non-Metals have no luster. 2. Non-Metals usually don't reflect heat and light. 3. Non-Metals do not conduct heat and electricity. 4. Non-Metals are non ductile and cannot be drawn into wire. 5. Non-Metals are non-malleable and can not form sheets.

Homogeneous and Heterogeneous Mixture

Homogeneous Mixture

1. Those mixtures, which have uniform composition throughout their mass are called homogeneous mixtures. 2. Homogeneous mixture has only one phase through out its mass. 3. Homogeneous mixture are also known as solution. 4. Examples: Salt and water, Sugar and water. Heterogeneous Mixture

1. Those mixtures, which do not have uniform composition through their mass are called Heterogeneous Mixture. 2. Heterogeneous Mixture has more than one phase through out its mass. 3. Heterogeneous Mixture are not solutions. 4. Examples: Rocks, Soil, Food products.

Molecular and Empirical Formula

Molecular Formula

1. Formula which shows the actual number of atoms of each element present in a molecule is called Molecular Formula. 2. Molecular Formula shows the structure of compound. 3. Two or more compounds cannot have same Molecular Formula. 4. Molecular Formula = n x Empirical Formula. 5. It represents covalent compounds only. Empirical Formula

1. formula, which shows the relative ratio of atoms of each element present in a molecule, is called Empirical Formula. 2. Empirical Formula can not show the structure of compound. 3. Two or more compounds can have same Empirical Formula. 4. Empirical Formula = Molecular Formula / n 5. It represent an ionic compound as well as a covalent compound. @import "/extensions/GoogleAdSense/GoogleAdSense.css";

Symbol and Formula

Symbol

1. A symbol is an abbreviation for the chemical name of an element and represents only one atom of the element. 2. It represents one atom of an element. 3. Symbol is written for elements. 4. Examples: Na, Br, Cl, F etc.

Formula

1. Representation of compound in terms of symbols is called formula. It represents one atom of an element. 2. It represents atoms of same or different elements present in one molecule. 3. It represents an ionic compounds as well as a covalent compound. 4. Examples: H2O, NH3 etc.

Gram and Gram Molecule

Gram

The atomic mass of an element expressed in grams is called gram atomic mass. 2. It is associated with element only. 3. It is the mass of one atomic mole. 4. One gram atom of any substance contains 6.02 x 10(23) atoms. (23 is the power of 10). Gram Molecule

1. Molecular mass of any element or compound expressed in grams is called gram molecule. 2. It is associated with element and compound. 3. It is the mass of one molecular mole. 4. One gram molecule of any substance contains 6.02 x 10(23) atoms. (23 is the power of 10).

Atom and Molecule

Atom

1. It is the smallest particle of an element which can enter into a chemical reaction. 2. It is represented by a symbol of the element. 3. It shows the properties of the element. 4. It retains its identity in a chemical reaction. Molecule

1. It is the smallest particle of a substance which can exist and show all the properties of the substance. 2. It is represented by a molecular formula of the substance. 3. It shows the properties of the substance. 4. It does not retain its identity in a chemical reaction.

Exothermic and Endothermic Reactions

Exothermic Reaction

1. Those chemical reactions in which heat energy is evolved are called exothermic reactions. 2. In exothermic reactions the enthalpy of products is lower than the reactants. H is therefore negative for an exothermic reaction. 3. During endothermic reaction, the system becomes colder and net potential energy of substance increases. 4. The energy is absorbed during these reactions. 5. The temperature of reaction therefore decreases. Endothermic Reactions

1. Those chemical reactions in which heat energy is absorbed are called endothermic reactions. 2. In endothermic reactions the enthalpy of reactants is lower than the products. H is therefore positive in endothermic reaction. 3. During endothermic reaction, the system becomes colder and net potential energy of substance increases. 4. The energy is absorbed during these reactions. 5. The temperature of reaction therefore decreases.

Physical and Chemical Properties

Physical Properties

1. The physical properties of a substance are those characteristics which serve to distinguish it from other substance but do not deal with its ability to undergo chemical changes. 2. These are related to the physical state of matter. 3. Examples: Formation of ice from water, formation of a magnet from ice etc. Chemical Properties

1. The chemical properties of a substance indicate the ability of a substance to undergo chemical changes. 2. They are related to the chemical change of a substance. 3. Examples: burning of paper, rusting of iron.

Electrolyte and Non-Electrolyte

Electrolytes

1. Electrolytes conduct electricity in molten or in solution form. 2. These form positive and negative ions when dissolved in water e.g. NaCl form Na+ and Cl- ions when dissolved in water. 3. Chemical changes occur when electric current is passed through the electrolyte. 4. Generally these are ionic or polar covalent compounds. Non-Electrolytes

1. Non-electrolytes do not conduct electric current in molten or in solution form.

2. These do not form positive and negative ions when dissolved in water e.g. Urea, sugar, glucose etc. 2. No chemical change occurs in them on passing current. 3. Generally these are non polar covalent compounds. 4. Generally these are non polar covalent compounds.

Acid and Base

Acid

1. Those compounds which provide hydrogen ion (H+) in aqueous solutions are called Acids. 2. An acid is a substance which produces H+ ions in aqueous solution. 3. Acid is a species (a compound or ion) which donates or tends to donate a proton (H+). 4. An acid is a species (molecule or ion) which can accept a pair of electron. An acid is also called an electrophile (electron loving). 5. They have sour taste. 6. Acid turn blue litmus red methyl orange red. Base

1. Those compounds, which provides hydroxyl (OH-) ion in aqueous solution, are called bases. 2. A base is a substance, which gives (OH-) in aqueous solution. 3. A base is a species, which accepts or tends to accept a proton. 4. A base is a species (molecule or ion) which can donate a pair of electrons. A base is also called a nucleophile (Nucleus loving). 5. Bases have bitter taste. 6. Bases turn red litmus to blue, colorless phenolphthalein to pink and methyl orange to yellow.

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Ionic and Covalent Bond

Ionic Bond

1. Ionic bond is formed by complete transfer of electrons from one atom to another atom. 2. Ionic bond is always formed between different atoms. E.g. NaCl, CaCl2. 3. In ionic bond atoms have very large electro-negativity and ionization energy difference. 4. This bond is usually formed between metals and non-metals. 5. This bond is very strong. 6. As a result of this bond ionic compounds are formed. 7. It is always formed between two different atoms. 8. It is formed when difference of electro-negativity of combining atoms is 1.7 or more. Covalent Bond

1. Covalent bond is formed by the mutual sharing of electrons between two atoms. 2. Covalent bond may be formed between similar or dissimilar atoms e.g. H2, O2, HCl etc.

3. In covalent bond atoms have very small electro-negativity or ionization energy difference. 4. This bond is usually formed between non-metals only. 5. This bond is comparatively less strong. 6. As a result of this bond covalent compounds are formed. 7. It is formed between similar and different types of atoms. 8. It is formed when difference of electro-negativity of combining atoms is less than 1.7.

Ionic and Covalent Compounds

Ionic Compounds

1. The ionic compounds are usually solid, hard and brittle. 2. The ionic compounds are good conductors of electricity either in fused state or in the form of aqueous solution. 3. Ionic Compounds have high melting points and boiling points. 4. Ionic compounds have high melting points and boiling points. 5. Covalent compounds are mostly volatile. Covalent Compounds

1. Covalent compounds exist in all the three states i.e. gas, liquid and solid. 2. A pure covalent compound does not conduct electricity. 3. These have usually low melting and boiling points. 4. These are soluble in water. 5. These are insoluble in water but soluble in organic solvents.

Co-Ordinate Covalent and Covalent Bond

Co-Ordinate Covalent Bond

1. It is a bond in which the shared electron pair is denoted by one atom only. 2. One atom donates electrons but other has no contribution. 3. Lewis acids and bases always from this bond. 4. It is represented by ->. 5. It is formed by the donation of an electron apir by one of the two bonded atoms. 6. It is formed by the completely filled atomic orbital. Covalent Bond

1. It is a bond formed by the mutual sharing of electrons. 2. In the shared electron pair both atoms have equal contribution. 3. Lewis acids and bases do not form this bond. 4. It is represented by _. 5. It is formed by the mutual sharing of electrons between atoms. 6. It is formed by the overlap of partially filled atomic orbital.

Polar and Non-Polar Covalent Bond

Polar Covalent Bond

1. The covalent bond between two atoms having different electro-negativity is called a polar covalent bond. 2. In a polar bond, the shared electron pair is not equally attracted by the bonded atoms. 3. Bonded atoms become slightly charged and acquire partial =ve and -ve charges. 4. It has an ionic character. 5. The bond energy is greater. Non-Polar Covalent Bond

1. The covalent bond between two atoms having same electro-negativity is called a non-polar covalent bond. 2. In a non polar bond, the shared electron pair is equally attracted by the bonded atoms. 3. Bonded atoms remain electrically neutral and do not acquire partial charges. 4. It has no ionic character. 5. The bond energy is lesser.

Electrolytic and Galvanic or Voltaic Cell

Electrolytic Cell

1. It is a device for converting electrical energy into chemical energy. It means by passing current through an electrolyte, chemical reaction takes place. 2. It consists of a vessel containing an electrodes and a source of direct current (battery). 3. Example: Electrolysis of aqueous solution of NaCl. Galvanic or Voltaic Cell

1. It is a device for converting chemical energy into electrical energy. It means spontaneous redox reaction is used for the production of electric current. This cell was prepared by L.Galvani and A.Volts, hence named as Galvanic or Voltaic Cell. 2. It consists of two half-cells. Each half cell consists of an electrodes and the solution with which it is in contact. 3. Example: Daniel Cell-Zn/ZnSO4 and Cu/CuSO4 cell.

Solution and Suspension

Solution

The size of particles is between 0.1 to 1nm. 2. Particles cannot be seen with low power microscope. 3. It is homogeneous.

4. Particles do not settle down. 5. It is transparent. 6. Components cannot be separated by filtration. Suspension

1. The size of particles is larger than 1000nm. 2. Particles can be seen by low power microscope. 3. It is heterogeneous. 4. Particles settle down. 5. It is not transparent. 6. Components can be separated by filtration.

« on: July 02, 2010, 06:37:46 PM »

Acidity

The acidity of a base is defined as the number of ionizable hydroxyl groups in its molecule. Anode

It is an electrode through which electrons enter the external circuit. Alpha Rays

There are positively charged particles emitted from a radioactive substance. They carry two positive charges and are called helium nuclie. Analytical Chemistry

It is the branch of chemistry which discusses the analytical methods forgetting information about chemical compounds and chemical processes. Atomic Number

Number of positively charged particles (protons) present in the nucleus of an atom. Atomic Size

Average distance between the nucleus of an atom and its outermost electronic shell. Its units are nm or pm. Arrehenius Acid

It is a chemical compound which gives proton (H+) in water. Arrehenius Base

It is a chemical compound which gives hydroxide ion (OH-) in water. Atomic Spectrum

Spectrum of radiations emitted by the excited atoms when they come to the normal state. Acidic Salts

An acidic salt is obtained when hydrogen atoms present in an acid, are partially replaced by metallic atoms. Alchemist

A scientist trying to convert cheaper metals into precious metals is called Alchemist and this branch of chemistry is called Alchemy. Atomic Mass

The mass of an element relative to the unit mass, which is 1/12th o the mass of C-12. Ampere

The amount of electric current which liberate one electrochemical equivalent of a substance per second during electrolysis of that substance is called ampere. Biochemistry

It is the study of chemical compounds present in living things. Balancing of Chemical Equations

Equating the atoms of reactants with those of products. Beta Rays

These are electrons emitted from a radioactive substance. Brownian Movement

The free movement of the molecules of gases and liquids is called Brownian movement. Bronsted Acid

A compound which can donate proton. Bronsted Base

A compound which can accept proton. Basicity

The basicity of an acid is defined as the number, of ionizable hydrogen atoms present in its molecule. Basic Salts

A basic salt is obtained when the hydroxyl groups present in a base are partially replaced by some other groups. Boiling Point

A temperature at which a liquid changes into gaseous state. Chemistry

The branch of science, which deals with the composition of matter changes in matter and the

laws or principles which govern these changes. Chemical Equation

The representation of a chemical change in terms of symbols and formulas. Covalent Solid

A solid in which there exist a covalent bond between atoms. Covalent Bond

It is the force of attraction that arises between two atoms due to mutual sharing of an electron pair. Co-Ordinate Covalent Bond

When the shared pair of electrons is provided by one of the bonded atoms, a coordinate covalent bond is formed. Cohesive Forces

The forces of attraction present between the particles of solid, liquid and a gas. Cathode Rays

Rays emitted from cathode in the discharge tube. Colloidal Solution

A solution in which solute particles are bigger than those present in a true solution and which cannot be filtered. Conductor

A substance which allows electric current to pass through it. Cathode

It is an electrode through which electrons leave the external circuit. Concentration of a Solution

The amount of a solute which has been dissolved in a particular amount of a solvent. Concentrated Solution

A solution, which contains an excess amount of a solute as compared to that of a solvent. @import "/extensions/GoogleAdSense/GoogleAdSense.css";

Cell

The vessel containing reacting substances in which transfer of electrons takes place is called cell. Coulomb

It is unit of electric current. When one ampere electric current is passed for one second the

quantity of electric current is one coulomb. Discharge Tube

A glass tube containing a gas at a very low pressure and provided with electrodes to study the passage of electricity through the gas. Dipole-Dipole Forces

The forces of attraction which originate due to the difference in electro negativities of the bonded atoms in polar molecules. Diffusion

The movement of molecules from a higher concentration to a Lowr concentration is called Diffusion. Dilute Solution

A solution, which contains a small amount of a solute as compared to that of a solvent. Double Salts

When two typical salts are crystallized together a double salt is formed. The physical properties of the crystals of double salt are different from those of the component salts. Doberiner's Law of Triads

Dobereiner arranged similar elements in sets of three, called Triads. Atomic mass of the middle atom of a triad was equal to the average of the atomic masses of first and third members. Degree of Ionization

It is the extent to which an electrolyte ionizes in water. Experiment

An experiment is an activity performed under suitable conditions with specially designed instruments to get the required information. Empirical Formula

The formula of a compound which shows the minimum ratio present between the atoms. Electron Affinity

The amount of energy given out when an electron is absorbed in the outermost electronic shell of all isolated gaseous atom. Its units are KJ/mol. Electro-Negativity

It is the power of an atom to attract the shared pair of electrons. Evaporation

The continuous escape of the molecules of a liquid from its surface. Elastic Collision

When gas molecule collides with each other their total energy does not decrease or increase. This type of collision is called an elastic collision. Electrolytic-Cell

In a non-spontaneous oxidation-reduction reaction takes place with the help of electrical energy. Electro-Chemistry

It is that branch of chemistry in which chemical energy is converted into electrical energy or electrical energy is converted into chemical energy. Electrolytes

When electricity is passed through an ionic compound which is either in the fused state or in the form of aqueous solution, it is decomposed into its constituents. The ionic compound is called an electrolyte. Electrolysis

The passage of electricity through an electrolyte is called electrolysis. Electrochemical Series

A list of ions in which they are arranged in the order of their ability to get discharged. Electroplating

The process of depositing a metal on another metal with the help of electricity. Exothermic Reaction

Those chemical reactions during which heat is evolved. Endothermic Reactions

Those chemical reactions in which heat energy is absorbed. Enthalpy of Reaction

Heat of reaction which takes place at constant pressure. Formula Mass

Formula mass is the mass of compound relative to the unit mass which is 1/12th of the mass of C-12. Farad

It is the unit of charge 1 farad = 96500 coulomb. Fusion

When a solid change into liquid this phenomena is called Fusion. Heat of Neutralization

The heat given out during a neutralization reaction is called heat of neutralization.

Heat of Reaction

Heat evolved or absorbed during a chemical reaction which takes place at pressure. Hypothesis

In the light of experiments, the scientists try to explain observations and facts. This tentative explanation is called hypothesis. It is quite possible that after sometime, on the basis of new experiments this hypothesis may be rejected. Hydrogen Bonding

When a hydrogen atom is attached to any one of fluorine, oxygen and nitrogen atoms, there appears strong dipole forces which are called hydrogen bonding. Hydrated Ions

Ions of a solute surrounded by water molecules are called hydrated ions. Ionization

An electrolyte splits up into charged particles upon heating or in its aqueous solution. This process is called Ionization. Ionic Theory

A theory which explains the process of electrolysis. Intermolecular Forces

The forces of attraction present between the molecules of a compound. Ionization Energy

The minimum amount of energy required to remove an electron from the outermost electronic shell of an isolated gaseous atom. Its unit is KJ/mol. Ionic Bond

A bond formed due to the electrostatic force of attraction between oppositely charged ions. Ionic Solid

A solid which is made up of ions of opposite charges. Isotope

Atoms of an element having the same atomic number but different mass number. Inorganic Chemistry

The study of all elements and their compounds except carbon is called inorganic chemistry. Industrial Chemistry

The application of chemical knowledge in technology and industry and the preparation of industrial products are called industrial chemistry. Inference

To deduce results after coordinating the observed facts with integrated scientific knowledge is called inference. Kinetic Theory

The theory which explains the composition and properties of all the three states of matter. Lewis Acid

A substance which can accept an electron pair. Law

A theory when repeatedly gives the same results after experimentation and offers correct explanation of scientific facts it then becomes a law or principle. Law of Conservation of Mass

Total mass of reactants is equal to that of products during a chemical reaction. Law of Definite

A compound always contains elements combined together in a fixed ratio by mass. Law Multiple Proportions

When two elements combine together to give more then one compounds, the different masses of an element, which combine with the fixed mass of the other element, have a simple ratio between them. Law of Reciprocal Proportions

When two or more elements A and B combine separately with the fixed mass of the third element E the ratio in which they do so may be the same or some simple multiple of the ratio in which these two elements (A and B) combine with each other. Molar Solution

A solution in which one mole of a solute has been dissolved in one dm3 of solution. It is represented as M. Metallic Bond

When positively charged metal ions are held together by freely moving electrons, the bond formed is called a metallic bond. Molecular Solid

A solid which has Vander Waal's forces present between its molecules. Melting Point

A temperature at which a solid changes into a liquid. Mass Number

The total number of protons and neutrons present in the nucleus of an atom. Mendeleyv's Periodic Law

Properties of elements are a periodic function of their atomic masses.

Modern Periodic Law

Properties of elements are a periodic function of their atomic numbers. Molecular Mass

Molecular mass is the mass of an element or a compound relative to the unit mass, which is 1/12th of the mass of C-12. Molar Mass

The mass of an element or a compound which contains Avogadro's number particles. Molecular Formula

The formula of an element or a compound which tells the actual number of atoms present in the molecule of that element or a compound. Neutralization

Acids and bases react together to form salts and water and in this way they neutralize the properties of each other. This reaction is called Neutralization reaction. Normal Salts

Salts, which neither have replaceable hydrogen atoms nor hydroxyl groups. Non-Conductor

A substance through which electric current cannot pass. Neutron

It is the smallest neutral particle present in the nucleus of atoms. Its mass is slightly more than that of a proton. Nucleus

Central part of an atom where most of its mass is concentrated. Its size is very small as compared to the size of the atom. Newland's Law of Octaves

If elements are arranged in the increasing order of their atomic masses every 8th element repeats the properties of the 1st element.

Oxidation

A chemical reaction in which oxygen is added or hydrogen is removed or electrons are lost. Octet Rule

When an atom has eight electrons in its outer most shell, its is said to be stable and does not combine with other atom to reduce its energy. This is called octet rule. Organic Chemistry

The branch of chemistry in which we study the compounds of carbon.

Observation

The process of observing natural phenomena with the help of five senses and the scientific equipment.

Orbits

The circular path of an electron around the nucleus. pH Scale

The negative log of hydrogen ion (H+) concentration present in a solution is called pH. This scale measures the concentration of hydrogen ions present in a solution. Percentage by Mass

Volume of a solute present in 100cm3 of a solution. Percentage by Volume

Volume of a solute present in 100 cm3 of a solution. Physical Chemistry

The branch of chemistry, which deals with the physical properties and physical behaviour of material things. Prediction

The inference based on observed facts. Proton

It is the smallest positively charged particle present in all kind of atoms. The mass of this particle is equal to the mass of the hydrogen nucleus (H+). Positive Rays

Rays produced in the discharge tube, which are traveling in a direction opoposite to the cathode rays. Reversible Reaction

Chemical reaction, which takes place both directions, forward as well as backward. Reduction

A chemical reaction in which hydrogen is added or oxygen is removal or electrons are absorbed. Radioactive Rays

Rays emitted from radioactive element or their compounds, which can cause fogging of the photographic plate. Strong Acid

An acid which ionizes completely in water. Strong Base

A base which can ionize completely in water giving excess of hydroxide ions.

Sublimation

Some solids, upon heating, change directly into vapors instead of changing into liquid. Scientific Method

The method which helps to collect facts on the basis of observations and experiments. Theories and laws are then formulated to explain these facts. Solute

The substance present in relatively lesser amount in a solution. Solvent

the substance present in excessive amount in a solution. Solvated Ions

Ions of a solute surrounded by solvent molecules in a solution are called solvated ion. Saturated Solution

A solution, which contains the maximum amount of a solute at a particular temperature and which is unable to dissolve further amount of solute in it. Supersaturated Solution

A solution which contains an amount of solute more than that required for the preparation of a saturated solution at a particular temperature. Standard Solution

A solution whose concentration is known. Solubility

The amount o solute in grams which can dissolve in 100 gm of solvent at a particular temperature to give a saturated solution. Suspension

A mixture in which solute particles do not dissolve in solvent. Strong Electrolytes

An electrolyte which completely ionize in water. Transition Elements

Elements having incomplete penultimate (next inner to the outermost) electronic shell. Theory

If a hypothesis is accepted (after discussion and experimentation) it is called a theory. Thermo Chemistry

It is the branch of chemistry in which we study the heat changes during a chemical reaction. Unsaturated Solution

A solution, which can dissolve further amount of a solute at a particular temperature, is called unsaturated solution. Unified Atomic Mass Unit

Unit of a new scale, which is equal to 1/12th of the mass of C-12. Voltaic Cell

In a cell a spontaneous oxidation-reduction reaction is used to produce electric current. Weak Electrolyte

An electrolyte which undergoes partial ionization in water. Weak Base

A base which ionizes partially in water. Weak Acid

An acid which ionizes partially in water. Water of Crystallization

The number of water molecules present in the crystals of a solid.

Digestion of Food 9th Class Biology Notes « on: July 03, 2010, 09:49:14 AM »

First of all food comes in the oral cavity where the teeth crush and break the food and convert it into small particles. The tongue rolls the morsel of food and pushes it under teeth again and again so that the food is evenly divided into fine particles and the saliva secreted from the salivary glands gets mixed with the food. The saliva lubricates the food and makes the particles adhere to one another, forming a ball of food called bolus. Now the chemical digestion of food begins. Saliva contains an enzyme to digest starch in the food. The combined action of teeth, tongue and saliva pushes the bolus through the throat into the oesophagus, and then it reaches the stomach.

Definition of Digestion

Digestion is the process in which the insoluble and non-diffusible components of food are broken down and by the action of enzymes are converted into soluble and diffusible substance to be absorbed into the blood stream.

Types of Digestion


1. Mechanical digestion 2. Chemical Digestion Mechanical Digestion

In mechanical digestion, the food consisting of large sized particle is broken into fine pieces by cutting, grinding, chewing and churning up, so that enzymes can act upon it efficiently and effectively. Mechanical digestion of food takes place in the mouth and stomach. Chemical Digestion

In chemical digestion, the digestive enzymes mix with the food and act upon it to break it down further into simple and diffusible chemical forms. The enzymes act on carbohydrates, proteins and fats separately. Chemical digestion takes place in all the major parts of the digestive system. The digestive glands such as liver and pancreas also play very important role in this digestion.

Digestive System

All living things require food to live and carry on their life functions. Animals are unable to synthesize their food. Digestion is the process in which the non-diffusible molecules of food are changed to diffusible ones by the action of enzymes. All the organs which take part in this process make a system which is called the digestive system.

Human Digestive System

The process of digestion takes place in the alimentary canal. It starts from the mouth and ends at the anus. The tube assumes different shapes according to their role in the process of digestion. It consists of the mouth, oesophagus, stomach, small intestine, and large intestine. Besides these organs liver and pancreas, also play important roles in digestion. Peristalsis

The muscles of alimentary canal produce rhythmic waves of contraction which is called peristalsis. Due to this process, food is carried through various parts of the alimentary canal. Ingestion

The food of animals and human is in the solid form and may be bulky. Taking in of the food in the oral cavity and swallowing is called ingestion. @import "/extensions/GoogleAdSense/GoogleAdSense.css";

Digestion of Food in the Mouth

During mastication, the food is mixed thorougly with the saliva while the food is in the oral cavity (buccal cavity). The saliva is secreted by three pairs of salivary glands located in the buccal cavity. The saliva is continuously secreted by the salivary glands in response to the presence of food in the buccal cavity.

Saliva is alkaline and contains an enzyme ptyalin. This enzyme converts starch into sugar (maltose). The morsel of food after being chewed and thoroughly mixed with the saliva is called a bolus. It is rolled down by the swallowing action into the oesophagus which conveys it to the stomach by the wave of peristalsis. The end of stomach lined with oesophagus is called cardiac end.

Digestion of Food in the Stomach

Stomach is a thick sac like structure, in which food is stored for some time. Its wall is strong and muscular. Its inner surface has numerous glands called gastric glands. These glands secrete a juice called gastric juice. Human stomach secretes about one to two liters of this juice daily; Gastric juice contains Hydrochloric acid and two enzymes, renin and pepsin. Hydrochlroic acid changes the medium of food to acidic. This medium kills the bacteria that may be found in the food. the pepsin acts on proteins and breaks them down into peptones. Renin helps to curdle milk in infants. There is no chemical action on carbohydrates and fats present in food. the regular movements of the stomach churn up the food. the food is changed into a thick fluid called chyme. When digestion in the stomach is complete, the distal end of the stomach called the pyloric end relaxes, and allows a small amount of chyme to pass into the first part of the small intestine. Food stays in stomach for about 2-3 or 3-4 hours.

Digestion of Food in the Small Intestine

Food from stomach enters the duodenum which is the first part of the small intestine. An alkaline pancreatic juice from the pancreas and bile juice from the liver and poured into the duodenum by a common duct. Both the juices contain bicarbonates which neutralize the acidic chyme and make. It rather alkaline besides these juices other intestinal juices from the walls of the small intestine are also poured. These entire juices act on food and help in digestion of food.

Liver

It is largest gland, in the body. Its colour is reddish brown. It lies just below the diaphragm on the right side of the body under the ribs. It has five lobes, three on the right side and two on the left. The cells of the liver secrete a greenish yellow alkaline fluid which is called the bile juice. It contains bile salts and bile pigments which give greenish yellow colour to the juice. Bile contains no digestive enzymes, but it does contain bile salts which break down the large molecules of fats to small fat droplets. This process is called emulsification. This process helps in the digestion of fats. Bile juice also contains bile pigments that are by products of red blood cells, these pigments are eliminated from the body along with the faeces, and the colour of faeces is due to these pigments. Besides this, bile juice also kill the germs in the food. Functions of Liver

1. Liver stores glycogen and regulates the level of glucose in the blood. 2. It breaks down excess amino acids. this process is called deamination.

3. It is involved in detoxification. 4. It produces and secretes bile juice which is stored in the gall bladder. 5. It metabolizes carbohydrates, fats, proteins and other compounds. 6. As a result of chemical changes a lot of heat is produced, therefore liver helps to keep the body warm. 7. It makes fibrinogen and other blood proteins. 8. It decomposes the damaged red blood cells.

Pancreas

It is a leaf like organ. It lies below the stomach and between the two arms of duodenum. The pancreas produces a juice which is called the pancreatic juice. This juice flows down the pancreatic duct into the duodenum. It contains three enzymes. 1. Pancreatic amylase which acts on undigested starches of the food and converts them into maltose. 2. Enzyme trypsin which breaks down proteins into peptides. 3. Lipase which splits fats into fatty acids and glycerol. If any of the constituents of food still remain undigested, enzymes secreted by the glands in the small intestine act upon them and complete the digestion by converting peptides to amino acids, maltose and other sugars to glucose and fats to fatty acids and glycerol. The enzymes secreted by the intestinal walls are amino-peptidases and disaccharidase,(which form glucose from maltose, lactose and sucrose). In this way food is completely digested at intestine.INTRODUCTION TO PHYSICS.

DEFINITION OF PHYSICS

The science of the nature. Physics is that branch of science which treats of laws and properties of matter and force acting upon it. The department of natural science (Physics) which treats the causes (Electricity, Head, Light, Magnetism) that modifying the general properties of body; natural philosophy.ORPhysics is an important branch of Science which offers the study of matter and energy along with the interaction between them.

BRANCHES OF PHYSICSThere are many branches of physics:1. Electronics"It is the branch of Physics which deals with development of electrons, emitting the devices and utilization and controlling of electrons flow in electrical circuit designed for various purpose." 2 Kinemetics"It is the branch of Physics which deals with description of motion without reference to any opposing or external force". 3. Optics"It is the branch of Physics which deals with light and its properties. 4. Dynamics

"It is the branch of Physics which deals with causes of motion and their effects" 5. Calorimetery"It is the branch of Physics which deals with measurement of heat". 6. Atomic physics"It is the branch of Physics which deals with properties and structure of Atom". 7. Mechanics"It is the branch of Physics which deals with motion of particles or bodies under the action of given force". CONTRIBUTION OF MUSLIMS SCIENTISTS 1. IBNE-AL-HAITHAM(965-1039 A.D)INTRODUCTIONHe was born in Basra a city of Iraq. He was one of the great Muslim Scientist. He was a freat scholar of physics,mathematics,engineering,astronomy and medicine.CONTRIBUTION1, He was a first man who discussed in detail about the luminous, non-luminous and transparent bodies.2, He also gave the structure and working of eyes.3, He gave us many laws of reflection and wrote many books about the reflection of light.4, He also first time gave the idea that whenever the ray of light is incident on an object some of the incident rays are reflected from the object and enter the eyes consequently the object becomes visible to the eyes which is accepted the scientific view. 2. AL-BERUNIINTRODUCTIONHe was born in Berun a small town of Afghanistan.He wrote many books on various subjects like physics,mathematics,culture,astronomy e.t.cCONTRIBUTION1, He discussed in detail about the movement of sun moon and others planets .2, He determined the densities of various metals .3, He gave an idea that Earth is floating in the sky like a ships in the water.4, He also awarded that he was a first who said that the velocity of light is more than the velocity of sound. 3.MUHAMMAD IBNE MUSA KHAWRZMIINTRODUCTIONAbu Abdullah Muhammad Ibn Musa al-Khwarizmi was born in 850A.D at Khwarizm (Kheva), a town south of river Oxus in present Uzbekistan.CONTRIBUTION1, Al-Khwarizmi was one of the greatest mathematicians ever lived. He was the founder of several branches and basic concepts of mathematics. He is also famous as an astronomer and geographer.2, He developed in detail trigonometric tables containing the sine functions, which were later extrapolated to tangent functions.3, Al-Khwarizmi also developed the calculus of two errors, which led him to the concept of differentiation. He also refined the geometric representation of conic sections.4, Al-Khwarizmi wrote a book on astronomical tables. Several of his books were translated into Latin in the early l2th century by Adelard of Bath and Gerard of Cremona. The treatises on Arithmetic, Kitab al-Jam'a wal-Tafreeq bil Hisab al-Hindi, and the one on Algebra, Al-Maqala fi

Hisab-al Jabr wa-al- Muqabilah, are known only from Latin translations.5, He was a first man who introduce the decimal system in mathematics.

Biology Class 9th IMP fill in blanks

Complete the following sentences with appropriate answers:

1. Cell was discovered in 1665 by _________.2. Fungi cannot make their own food because they lack _________.3. The physical and chemical breakdown of food in humans first begins in the _________.4. During respiration _________ is released from food.5. The different parts of human body and their functions are described in the book _________ written by Abdul Malik Asmai.6. The study of tissues is called _________.7. The hormone insulin is secreted by _________.8. Tape-worm belongs to the phylum _________.9. The fourth whorl of a flower is known as _________.10. Stem increases in thickness due to _________.11. The distance between two nodes of a stem is called _________.12. “Al-Mansoora” is written by _________.13. The third eyelid (transparent membrane) that protects the eye of frog in water is known as _________.14. The organs of locomotion in _________ are called Setae.15. _________ supplies blood to the brain and to the parts associated with the brain of forg.16. The genes representing a pair of contrasting characters are called _________.17. Firdous-ul-Hikma is written by _________.18. Star-fish belogns to the phylum _________.19. Androecium is the _________ whorl of a flower.20. Goitre is caused by the deficiency of _________.21. Fish respires by means of special structures called _________.22. _________ controls all functions of a cell.23. A long narrow and cylindrical fruit of Brassica compestris is called _________.24. The transfer of pollen grains from another to the stigma of carpel is called _________.25. Excretory organs in insects are called _________.26. The single major contribution of Muslim scientists in the field of scientific method is use of _________.27. The two main subdivisions of biology are _________ and _________ each of which has several further branches.28. Life can be best defined by comparing _________ of living things with those of _________ things.29. When food is burnt in our cells in the presence of oxygen to produce energy the process is called _________.30. When a cell divides to produce two new cells exactly like the parent the process is called _________.31. The sum of chemical reaction in cells is called _________.32. Cells were described for the first time by _________.

33. The tiny organs of a cell are called _________.34. Fungi cannot make their own food because they lack _________.35. Mosses belong to the group called _________.36. Invertebrates with spiny skins and hard plates, are known as _________.37. Birds possesses _________ bones.38. The major distinguishing feature of vertebrates in the presence of _________.39. Mango is an Angiosperm plant with two cotyledons. So it belongs to the subgroup called _________.40. The internal factor necessary for photosynthesis in plants is _________.41. Glucose produced by photosynthesis may be transformed into complex carbohydrates and other _________ which are utilized by plants or stored in edible plant parts.42. Plants, which feed on other plants and harm them, are called _________.43. Plants that feed on dead organic matter are called _________.44. Some plants are specially adapted to get their food by _________ mode of nutrition.45. Organic compounds in our food consisting of carbon, hydrogen and oxygen are called _________.46. Glucose and fructose combine to form a 2-sugar carbohydrate called _________.47. One gram of glucose releases about _________ calories of energy.48. The total number of known amino acids is _________.49. All organisms need food for _________.50. The building blocks of proteins are _________.51. Physical and chemical breakdown of food in man first begins in the _________.52. The blind sac at the juction of small and large intestine is called _________.53. Wave-like automatic contractions of the gut are called _________.54. The basic processes of transport of substances in cells of all organisms are _________ and _________.55. Plants transport water, minerals and food from region to region by a _________ system.56. Too rapid evaporation of water in hot weather causes loss of _________ pressure in plant cells and _________ of plants.57. Leaves remain cool even in sunlight due to the cooling effect of _________.58. Heart failure may occur due to _________.59. Hear muscle is different from _________ in working continuously and automatically without experiencing fatigue.60. A blockage in the _________ stops the flow of blood and oxygen to muscles of the heart.61. Respiration takes place in _________ cells of a plant while photosynthesis occurs only in _________ parts.62. During respiration _________ is released from food.63. Breathing means _________ of oxygen and carbon dioxide with the _________.64. Food is prevented from entering the larynx by _________ which guards the opening into it.65. Oxygen from the lungs is transported to the cells in the form of _________.66. The volume of the thoracic cavity increases when muscles of the rib cage and the diaphragm _________.67. The control center for breathing is located in the _________.68. The capillary network enclosed in Bowman’s capsule is called _________.69. Persons suffering from kidney failure can be helped either by such artificial means as _________ or by _________ transplants.

70. Excretion involves removal of _________, excess _________ and _________.71. Nitrogenous wastes are produced when _________ are metabolized.72. Extra quantities of CO2, O2 and water in plants is released through _________.73. Like animals, plants too are _________ to environmental factors.74. Any environmental factor to which plants react is called a _________ whereas the reaction itself is called a _________.75. Support and movement human being is a function of _________ and _________.76. The body of invertebrates such as arthorpoda is protected and supported by an _________.77. The joints of skull bones are of _________ types.78. Ligaments hold the _________ together.79. The type of muscle which makes possible movements of a vertebrate animal is called _________.80. Co-ordination of various activities of the body in multicellular animals is not possible without _________ systems.81. Single-celled organisms are too small to need special means of _________ of information.82. Large animals have developed two special systems of communication namely _________ and _________ systems.83. The structure which perceive environmental stimuli are called _________.84. The main effectors in the body of animals are _________ and _________.85. Glands without duct are called _________.86. Tissues and organs, which respond to hormones, are called _________ sites.87. The endocrine gland, which controls the function of thyroid, adrenal, ovary and testis, is called _________ gland.88. Hormones are substance made by _________ and are released directly into _________.89. Budding results in new individuals by the process of _________ division.90. The a***ual method of reproduction in yeast is _________.91. The 3rd and 4th whorls of flower are _________ and _________.92. Fusion of sperm with the egg results in formation of a _________ with _________ number of chromosomes.93. The part of the seed which contains nourishment for the embryo is called _________.94. The development of a tadpole to become an adult frog is called _________.95. The science which deals with the study of viruses, bacteria, protozoa and microscopic fungi is called _________.96. Some bacteria can reproduce so fast that they can produce almost _________ generations in 24 hours.97. Food can be preserved by _________, _________ and _________.98. Genetic engineering is a branch or area of _________.99. Biological principles which explain similarities and differences among individuals are called _________.100. The science which deals with structure and working of DNA and genes inheritance is called _________.101. Chromosomes consist of _________ and _________.102. An individual receives _________ percent of its chromosomes from each parent during ***ual reproduction.103. An ecologist specializes in learning about interrelationships _________ and their interaction with _________ environment.

104. The components of environment are _________ and _________.105. The place where organisms live is called _________.106. The different living thing component in an ecosystem constitute a _________.The basic functional unit of environment is an _________. __________________

BRYOPHYTES AND TRACHEOPHYTES.

BryophytesBryophytes are on of the two main groups of kingdom 'Plantae' the second being the 'tracheophytes'. Bryophytes is a group of plants which are multicellular, photosynthetic eukaryotes; and their reproductive organs are multicellular; their zygote develops into small, protected embryo that develops into a complete new hence bryophytes have also been called embryophytes. The cell of these plants is made up to cellulose. Characteristics of BryophytesThe important characteristics of Bryophytes are as follows:1. Bryophytes are plants without vascular tissue (xylem a phloem), whereas tracheophytes have vascular tissue. Therefore tracheophytes are vascular plants, whereas bryophytes are non-vascular plants.2. Bryophytes are the simplest land plants. Bryophytes divided into three groups. Liverworts, hornworts, and mosses.3. Marchantia is an example of liverworts; its plant body is a thick branched green thallus.4. Anthoceros is a horn wort, and Funaria is a moss.5. All bryophytes and generally found growing in moist habitants such as damp soil and rocks, moist brick walls, and along the banks of streams. Life Cycle of Funaria MossIt is a common moss found grwoing t moist places. Green leafy, moss plant of Furania, as like all Bryophytes, Funaria is haploid gametophyte, its height is about 0.5 - 1 inch.(Diagram) Gamatophyte GenerationIt consists of 3 parts:1. A vertical stem like structure.2. Leaf like photosynthetic structures arranged on the stem, which are composed of a single layer of cells, and without stalk.3. Numerous multicellular rhizoids, arising from the lower side of the stem and which absorb water and salts, and anchor the plant to the soil. Male *** organs, called antheridia (singular antheridium) are located at the tip of male branch, and the female *** organs, called archegonia (singular archegonium) are located at the tip of female branch.Fertilization takes place in the presence of water within the archegonium located at the tip of female branch. The zygote develops into the embryo (2n). The embryo forms the sporophyte (2n). The sporophyte remains attached to the tip of female branch. The sporophyte gets water, slts and also part of its food, from the parent gametophyte plant. Sporophyte GenerationThe sporophyte consists of three parts:1. A foot2. A long stalk like seta

3. Capsule The foot is anchored to the female branch and absorbs nutrients from the gametophyte. The seta elevates the capsule in the air. Within the capsule, haploid spores are produced by meiosis. The spores are dispersed by wind. Each spore develops eventually into new haploid gametophyte plant, and the life cycle continues.Like other bryophytes, Funaria also has well defined alteration of generations; haploid gametophyte generation is dominant, whereas diploid sporophyte is attached to and more or less dependent on the gametophyte. Pteridophytes1. Unlike bryophytes the plant body in Pteridophytes is differentiated into root, stem and leaves.2. In contrast to other vscular plants Pteridophytes do not bear flowers, fruits and seeds.3. Due to presence of vascular tissues, they are similar to gymnosperms and angiosperms.4. Although the dominant generation in Pteridophytes is also the sporophyte but unlike gymnosperms and angiosperms both sporophyte and gametophyte generations are independent and free living. However, the gametophyte in much reduced and smaller in size. SpermatophytesSeed plants or Spermatophytes are that group of vascular plants which produce seeds. Seed is a ripened ovule. It contains a young plant with embryonic root, stem and one or more leaves, which has stored food material and is protected by a resistant seed coat or testa. Spermatophytes like pteridophytes possess vascular tissues. They also have life cycles with alternation of generations. Unlike bryophytes and pteridophytes, spermatophytes do not have free living gametophyte; instead the gametophyte is attached to and nutritionally dependend upon the sporophyte generation. Main Groups of SpermatophytesGymnospermsThey produce seeds which are totally exposed or borne on the scales of cones. AngiospermsThey are flowering plants which produce their seeds within a fruit. Pinus and Thuja - The Typical GymnospermPinus is normally grows at an altitude of 5000 ft to 8000 ft. It has many types e.g. chir, kail, chilghoza etc. However, some species are found in the plains. It is also grown as ornamental plants. Pinus tree is a sporophyte, which is evergreen and quite tall. It consists of an extensive root system and a strong, stout and woody stem and its branches. The upper branches progressively become shorter in length. In this way, the tree assumes a symmetrical conical shape.(Diagram) ThujaThuja (common known as Mor Pankh) is a short tree. It has profuse branches, which are covered with small, dark green scale leaves. It is conical in appearance. It is grown as ornamental plant in parks and homes. Leaves of ThujaThuja has small scale like green leaves that cover the stem. Female Cone of ThujaIn Thuja the female cones are spherical or oval in shape. These are about the size of a bair (berry). They consist of hard, brown colour scales with triangular apices. Pinus

Pinus has two types of shoots. Shoots of PinusLong Shoots or Shoots of Unlimited GrowthThey are formed on the main stem and continue growth indefinitely by buds borne at their apices. They are covered by scale leaves. Dwarf Shoots or Shoots of Limited GrowthThese shoots originate in the axils of the scale leaves on the long shoots. They are very short (only a few millimeters in length). Each dwarf shoot bears 1 t 5 foliage leaves in addition to scales leaves. Leaves of PinusScale LeavesThese are small, membranous and brown in colour. They cover the stem. Foliage Leaves or NeedlesThese are commonly long and narrow, tough, and leathery. In contrast to scale leaves they are green and photosynthetic. Depending upon the type of species, a cluster of 2 to 5 needles is produced on each dwarf shoot. Each dwarf shoot with its cluster of needles is called a spur. Reproduction in PinusPinus tree produces reproductive structures known as cones every year. Cones are of two types, male and female c9ones. Both male and female cones are produced on the same tree but on different branches. Male Cone of PinusMale cones, usually 1 cm or less in length, are much smaller than the female cones. They are produced in clusters. These are generally born on the lower branches of the tree. Each male cone is composed of spirally arranged leaf-like structures called scales or microsporophylls. Each microsporophyll has two long sacs called pollen sacs of microsporangia on it are under surface. A***ual reproductive cells, microspores or pollen grains are produced by meiosis in the microsporangia. Pollen grains are haploid. After being transferred to the ovule, the pollen grain forms pollen tube. It is the male gametophyte in which male gametes or sperms are produced. Female Cone of PinusThe female cones are much larger than the male cones. These are usually found on the upper branches. Each female cone is also made of spirally arranged scales which are called megasporophylls. These scales become woody on maturity. Two ovules are present side by side at the base of each scale. Haploid megaspores are formed in the ovule by meiosis. Measpores give rise to female gametophytes which produce female gametes. Fertilization results in the formation of embryo after which the ovule is ripened to form seed. Female cones normally remain attached for three years on the plant. On maturity the cones open up and the seeds are set free and dispersed. AngiospermsAngiosperms are the flowering plants which are most successful plants. They are more important than the gymnosperms. They have adapted to almost every type of environment. There are about at least 235,000 species. They are dominant plants. Angiosperms are vascular plants which bear flowers. Their seeds are produced within fruits. The fruit protects the developing seeds and also helps in their dispersal. Seed and fruit producing habit have helped flowering plants in their evolutionary success.Angiosperms are found in wide variety of sizes and forms. Ensize they range from over 300 ft in height (some species of Eucalyptus) to searcely 1mm in length (duckweed, Woiffia).

On the basis of size and woody texture, angiosperms are classified as herbs, shrubs (bushes) and trees. Herbs are the plants which are small in size. Their stems are Herbs which are then cut or pulled from the soil. In contrast shrubs and trees have hard woody stems, which retain their shape even after being cut. Shrubs are shorter than trees but have more branches. In addition to tracheids, angiosperms have efficient water conducting structures known as vessels in their xylem. Classes of AngiospermsOn the basis of the number of cotyledons in the seed, angiosperms are divided, into two classes.1. Monocotyledons or Monocots2. Dicotyledons or Dicots Monocots1. Monocot seeds have only one cotyledon or embryonic leaf.2. A nutritive tissue called "endosperm" is usually present in the mature seed.3. Monocots are mostly herbs with long narrow leaves.4. Leaves have parallel veins i.e. in the lamina of the leaf veins run parallel to one another.5. The floral parts of most flow3ers usually occur in threes or multiples of three (i.e. 3, 6, 9 ...)6. Monocots include different grasses, cereals (wheat rice, maize etc) ,palms, onions and lilies. Dicots1. Dicot seeds have two cotyledons.2. In mature seed, te endosperms is usually absent.3. Their leaves vary in shape but usually are broader than monocot leaves.4. Leaves have reticulate veins i.e. branched veins resembling a net. The flower parts are four or five in number or multiples of 4 or 5.5. Dicots include rose, peas and pulses, sheesham, Kiikar (Acacia), sarsoon (mustard), cacti, mango, orange and sunflower etc.

RESPIRATION

RespirationThe oxidation of the absorbed food material in order to obtain energy is called respiration.There are two types of Respiration in the organisms:1. Anaerobic Respiration2. Aerobic Respiration Aerobic RespirationIn most of the higher and larger organism, the glucose etc is oxidized by using molecular oxygen. This type of respiration is known as Aerobic Respiration. In aerobic respiration a mole of glucose is oxidized completely into carbon dioxide and water releasing enormous amount of energy. One glucose molecule in this respiration produces 686,000 calories of energy. Aerobic respiration thus produces 20 times more energy than the anaerobic respiration.In aerobic respiration food is oxidized in presence of molecular oxygen.

Stages of Aerobic RespirationThere are two stages of Aerobic Respiration: (a) External RespirationIn this stage, the organisms take the air (containing oxygen) into their bodies. This is called external respiration. this stage includes the transport of oxygen obtained from the inhaled oxygen to each cell of the body.

(b) Internal RespirationThe second stage is called internal respiration. It consists of the oxidation of glucose, amino acid and fatty acids etc, with molecular oxygen. In this stage all these reactions are included which extract the chemical energy of glucose and other compounds and store it in the form of ATP molecule, this respiration is also called cellular respiration as it occurs within cells.In the internal or cellular respiration glucose and other compounds are passed through such enzymatic reactions which release the chemical energy gradually in small amounts with the help of which ATP molecules are synthesized. Anaerobic RespirationSome organisms oxidize their food without using any molecular oxygen. This is known as Anaerobic Respiration. In this type of respiration considerably less amount of energy is released as compared with the other type of respiration.In anaerobic respiration a glucose molecule is broken down into two molecules of lactic acid with a release of only 47,000 calories of energy. Glucose --------> 2 Lactic Acid + Energy (47,000 calories) Importance of Anaerobic Respiration1. When earth came into being its environment was totally devoid of oxygen. The aerobic organisms cannot lie in anaerobic environment. The early organisms started respiration in the absence of oxygen to produce energy for survival of organisms.2. Some existing organisms like bacteria and parasites which live in oxygen environment have anaerobic respiration.3. Many useful bacteria and yeasts are anaerobic.4. Even in the aerobic respiration of the first phase is anaerobic. The glycolysis which is the first phase of carbohydrate metabolism involves reaction which does not require the expenditure of molecular oxygen. This proves the idea that aerobic organisms have evolved from anaerobic organisms.5. In our skeletal muscles, although aerobic metabolism takes place but in sustained activity when the oxygen supply cannot keep pace with energy demand, anaerobic respiration supplies the energy continuously by the breakdown of glucose to lactic acid. ATP (Adenosine Triphosphate) It is a chemical compound. ATP is an abbreviation of adenosine triphosphate. Its name indicates that it contains adenosine and three phosphate groups. Adenosine is formed of a nitrogenous base called adenine and a sugar called ribose. In ATP three phosphate groups are attached to the adenosine in a series one after the other. Significance of ATPATP is a big source of energy. The two terminal bonds between the phosphate groups contain large amount of the chemical energy. When these bonds are broken in enzymatic reaction, large amount of energy is released by which energy requiring activities are accomplished, like synthesis of various compounds of carbohydrates, fats, proteins and hormones etc or for carrying out any physical work like muscle contraction, heat production or transport of substances etc.When the terminal bond is broken the ATP is changed into ADP and phosphate 7300 calories of energy are released. Gaseous Exchange in PlantsPlants get their energy from respiration. Plants have no special organ or system fro exchange of gases. The gaseous exchange in plants occurs in cells, of every part of the plant i.e. roots, stems and leaves etc according to their energy demand. The conducting system (xylem and phloem) of

plants transports water and nutrients but plays no role in the transport of gases. The air spaces present between the cells of parenchyma of leaves, stem and roots are involved in the gaseous exchange. Gaseous Exchange in Leaves and Young StemsIn the leaves and young stems, gaseous exchange occurs through stomata. Some gaseous exchange also occurs through cuticle. Gaseous Exchange in Woody Stems and RootsIn woody stem and roots, there are present dead cells beneath the epidermis which form cork tissue. Later on, this tissue becomes porous. The pores are called lenticels. These are involved in gaseous exchange. Gaseous Exchange in LeavesThe aquatic parts obtain oxygen for their respiration by diffusion from the dissolved oxygen in water. Whereas the land plants get their oxygen from air directly through their stomata which are more abundant on the lower surface than the upper surface of leaves. Gaseous Exchange in RootsThe roots get their oxygen for gaseous exchange through diffusion from the air existing in the space between soil particles. Process of Respiration in PlantsThe respiration in plants continues day and night. In this process, the oxygen from the airspaces in the leaves and stems is diffused into tissues and cells after getting dissolved in the film of water which is present over the cells. In the cells this oxygen oxidizes the carbohydrates and other organic compounds into carbon dioxide and water to produce energy. Some of the water (vapours) comes in the airspaces from where they diffuse out to the atmosphere through lenticels and stomata. The elimination of carbon dioxide is more evident from the parts without chlorophyll like growing seeds and buds. The water produced in this process becomes a part of the already present water in the body of plants. The various chemical reactions of respiration are controlled by the specific enzymes. This process occurs at a faster rate in the parts of the plant having rapid growth like growing seeds, buds, apical meristem of roots and shoots, because these parts require more energy to accomplish the growth process. Relationship between Respiration and PhotosynthesisThe gaseous exchange in plant is not very evident during the day time as the products of respiration i.e. carbon dioxide and water are used in the process of photosynthesis. In the bright sunshine, because of high rate of photosynthesis the carbon dioxide produced in respiration falls short and therefore, some carbon dioxide has to be taken into the plant from outside for photosynthesis.In the day time the plants therefore, take in carbon dioxide and expel out oxygen. The process of photosynthesis occurs in chloroplasts whereas the process of respiration takes place in cytoplasm and mitochondria. Gaseous Exchange in AnimalsThe gaseous exchange in different animals takes place by different methods and organs. In unicellular aquatic animals like amoeba, the dissolved oxygen in water diffuses directly through their cell surface into the interior of the animal and the carbon dioxide similarly diffuses out from their bodies into the external water. This is the simplest way of gaseous exchange and it can occur only in small animals with a diameter of less than one millimeter. These animals have greater surface area of volume ratio and have low rate of metabolism. During evolution, as the animals became complex and complex and grew in their size, their skin

or external body surface become impervious to water. Thus the gaseous exchange became impossible through diffusion. In large animals certain organs were developed for exchange of gases w.g. the moist vascular skin, gills, lungs and tracheoles. These large animals have developed blood vascular system which transports oxygen from the respiratory surface to the deep cells and tissues in all parts of the body. The blood in all animals has some respiratory pigments like haemoglobin which carry large amount of oxygen efficiently from respiratory surface to the interior cells. Properties of a Respiratory Surface1. Respiratory surface should have large surface area.2. Respiratory surface should be moist.3. Respiratory surface should be thin walled.4. Respiratory surface should have blood supply. Gaseous Exchange Through SkinFor the exchange of gases through the skin the skin must be moist and richly supplied with blood. The oxygen is diffused from the external water to the blood and the carbon dioxide is diffused from the blood to exterior water. In amphibia and fishes the gaseous exchange occurs through the skin besides through the gills or lungs. The frogs and tortoises breath through the skin during their hibernation period. Gaseous Exchange by GillsThe gills are very effective for gaseous exchange in aquatic animals. Gills are of two types:(a) External Gills(b) Internal Gills (a) External GillsSome animals have external gills which project out of body of animals. These gills have very thin and highly vascularized surfaces e.g. the dermal papillae of star fish and arthropods. (b) Internal Gills These are present inside the body inner to skin e.g. in fishes and arthropods. Have you ever examined a fish closely? How ill you know that the fish is fresh or not? If the colour of gills is red then it is fresh but if the colour of gills is changed, it is definitely not fresh. The red colour of the fish gills shows the presence of oxygenated blood.

FOOD AND NUTRITION.

Need for FoodEverything needs energy to do some job e.g. to operate machines, electricity, steam, fuels like coal, petrol, wood etc are burned to get energy. Similarly, living organisms require energy to carry out their diverse activities of life. They maintain the complex structure of cells, excrete waste material, and reproduce for continuation of their race. They grow in size during their life span as they are small when born and are large when adult. A considerable amount of energy is required to carry out the functions of life. The organisms, therefore, need to have some source of energy in order to maintain their life. Organisms get their energy from food. The type of food depends upon the kind of organism using the food. Some organisms use inorganic compounds to get their energy requirements. Some organisms use vegetables (plants) while some others require flesh (animals) as their food.The organisms burn up their food (metabolize) to get a special form of energy called ATP (Adenosine triphosphate) which is used by them to carry out their functions of life.

Nutrients of Food and Their ImportanceThe food of organisms and the organic compounds, building their bodies are almost same. Their bodies are composed of carbohydrates, proteins and fats etc. These substances are used by organisms as their food. They get energy from these substances. They use the components of food in growth and repairing of damaged tissues. Thus substances acquired by organisms to obtain energy are called nutrients and the process by which they are obtained is called nutrition. The food of all organisms which depends upon already prepared food has been found to consist of six basic components. These are as follows:1. Carbohydrates2. Proteins3. Fats, Oils4. Vitamins5. Minerals6. Water

CarbohydratesThey are organic compounds. They are found in all organisms. They are commonly known as sugars. They contain three elements carbon, hydrogen and oxygen in which hydrogen and oxygen exists in 2:1 ratio that is why they are called hydrates of carbon or carbohydrates. One gram of carbohydrates provides 3800 calories of energy. Forms of CarbohydratesCarbohydrates occur in three forms.1. Monosaccharide2. Disaccharides3. Polysaccharides MonosaccharidesMonosaccharides are simple sugars. Their common example is glucose. Glucose is main source of energy in our body cells. DisaccharidesDisaccharides are formed by condensation of two monosaccharide units e.g. sucrose is formed by the combination of glucose and fructose. Maltose is another disaccharide. PolysaccharidesWhy many monosaccharides link together, they form polysaccharides. A single polyusaccharide may have many hundred units of monosaccharides. The common examples of polysaccharides are glycogen and starch. Glycogen occurs in animals and starch in plants. Another polysaccharide is cellulose, present in the cell walls of plants. It is the most abundantly occurring carbohydrate. Sources of CarbohydratesCarbohydrates containing starch are obtained from cereals and their products like wheat, rice, maize, oats and barley. They are also obtained from carrots, radish, turnip, beet, beet root and potatoes. Simple sugar called glucose is obtained from grapes. The sugar derived from fruit is called fructose. Then from beet and sugar cane is called sucrose and that from milk is lactose. Importance of Carbohydrates in Human BodyOne gram carbohydrate food provides 3800 calories to our body. The Carbohydrates are the cheapest and easy source of energy. Surplus carbohydrates are stored as glycogen in the liver and muscles, or converted to fats and stored in the fat cells beneath the skin and causes obesity.

Children, laborers and people, involved in physical labor need more carbohydrates in their daily diet whereas other should avoid them because their excess in the body can cause blood pressure, diabetes, obesity and heart diseases, therefore, carbohydrate products should be taken with care.

ProteinsProteins are very important organic compounds found in all organisms. Proteins contain carbon, hydrogen, oxygen and nitrogen and sometimes some amount of sulphur. There is no 2:1 ratio between hydrogen and oxygen. A protein molecule is composed of many building units linked together to form a chain. A chain of amino acids is called polypeptide. Amino acids are building units of a protein molecule. About twenty different amino acids occur in nature that combines in different manners to make different type of proteins. Proteins are structural part of the cell membrane. Some proteins are fibrous. They form different structures in the body like muscles, bones and skin. They also occur in our blood and cells. The enzymes which control different chemical reactions in the body are also proteins in nature. As a result of protein catabolism, energy is released. One gram of protein produces 4.3 kilo cal of energy which is used to synthesize ATP. Amino AcidsPlants can synthesize all the amino acids they need from carbohydrates, nitrates and sulphates but animals can not synthesize all amino acids. Amino acids are the building units of proteins.There are about twenty different types of amino acids which are used in the synthesis of protein found in the human body. Non-Essential Amino AcidsThere are many amino acids which a human body can synthesize within the body. These are called non-essential amino acids. Essential Amino AcidsThere are approximately ten amino acids, which human beings cannot make. These are called essential amino acids and can be obtained directly from proteins in the diet. Sources of ProteinsFollowing are the sources of proteins:Animal Sources e.g. meat, fish, chicken, milk and cheese. Plant Sources e.g. legumes, pulses, dry fruit and cereals. Importance of Proteins in Human Body1. Proteins are essentially required for growth and development.2. Growing children ,pregnant women and lactating mothers need a lot of proteins.3. An adult requires 50-100 gms of proteins daily.4. Protein deficiency in children and cause a disease called Kwashiorkor.5. Proteins play an important role in the building of cellular protoplasm.6. They also play an important role in the building of muscles and connective tissues.7. Many proteins are required for making enzymes, hormones and antibodies.8. If proteins are eaten in excess than needed by body, the excessive amino acids are converted into carbohydrates by the liver, which are either oxidized to release energy and converted into glycogen and fat and stored.

Fats and OilsThey are also organic compounds found in plants, animals and humans. They are very important compounds made up of carbon, hydrogen and oxygen. Fats contain more carbon and hydrogen as

compared to oxygen. A fat molecule has two parts, glycerol and fatty acids. Fatty AcidsDifferent kinds of fats contain different fatty acids. Fatty acids are basically of followin two types:1. Unsaturated Fatty Acids2. Saturated Fatty AcidsUnsaturated fatty acids (molecules with one or more than one double bonds) are liquids at room temperature and are called oils. These are good for human health. Saturated fatty acids (molecules without double bond) are solid at room temperature and are called fat. They are not good for human health because they increase cholesterol level in the body. They cause narrowing of blood vessels which may result in heart attack. Vegetable SourcesVegetable fats are liquid and are called oils e.g. mustard oil, olive oil, coconut oil, corn oil. etc. Animal SourcesAnimal fats are solids e.g. butter, ghee and fatty meat. Source of EnergyFats and oils are rich source of energy they provide double energy as compared to carbohydrates and proteins. One gram of fat on oxidation releases 9.1 kilo cal of energy to make ATP.

PhotosynthesisPhotosynthesis is a Latin word derived from two words photo (light) synthesis (building up). In this process, green plants manufacture carbohydrates from carbon dioxide and water. The energy needed for this process is obtained from sunlight, which is absorbed by chlorophyll and oxygen is produced as by-product. Leaves are the major sites of photosynthesis in most plants but all green parts of a plant including green stems; un-ripened fruit can carry out photosynthesis. Temperature also plays a very important role in photosynthesis. Temperature affects the rate of photosynthesis. This process occurs during day time only. Conditions and Factors Necessary for PhotosynthesisWaterPlants need water for many functions of life. Water enters the root hair from the soil. It passes through various cells and reaches the xylem of the root. From here it moves to the stem and then the veins of the leaves. Finally, it reaches the mesophyll cells in the leaves. It provides hydrogen for the synthesis of glucose and helps in opening and closing of stomata. If leaves get less water, less stomata open, this reduces the rate of photosynthesis. Opening of more stomata provide more carbon dioxide for photosynthesis. Carbon DioxideThis is an important factor which affects photosynthesis. The amount of carbon dioxide in the atmosphere is about 0.03% and does not vary much. Its amount differs from place to place which may affect the rate of photosynthesis. e.g. the concentration of carbon dioxide close to the ground in a dense forest is higher than in an open field. Although carbon dioxide is needed in very little amount by the plants, yet photosynthesis cannot take place without it. It diffuses from the air into the intercellular spaces through stomata and enters the chloroplasts in the mesophyll cells. Carbon dioxide provides carbon to build up glucose molecule. If the amount of carbon dioxide in the atmosphere increases to 1% rate of photosynthesis also increases, and it starts decreasing if concentration of carbon dioxide is decreased. If the concentration of carbon dioxide decreases below 0.03% the rate of photosynthesis also declines.

ChlorophyllIt is the green substance. It is found in special organelles called chloroplasts, which are found in the green leaves and herbaceous stems. In leaves, it is present in the mesophyll cells. Chlorophyll changes light energy into chemical energy and makes food in plants. Plants lacking chlorophyll cannot carry out photosynthesis occurs only in those parts where chlorophyll is present. SunlightLight is very important for the process of photosynthesis. Without light the photosynthesis cannot take place. It provides energy needed for the synthesis of glucose molecule. Light intensity varies from day to day and from place to place. Plants photosynthesize faster on a bright sunny day than on a cloudy day. While light consists of seven colours. The blue and red are best for photosynthesis. Is Chlorophyll Necessary for Photosynthesis?ExperimentSince it is not possible to remove chlorophyll from a leaf without killing it, so it becomes necessary to use a leaf where chlorophyll is present only in patches. Such a leaf is known as variegated leaf and a plant with such leaves is used in this experiment.For destarching the leaves, the pot is kept in a dark place for a couple of days and then exposed to day light for a few hours. The leaf is then removed from plant. Its outline is carefully drawn to note the position of presence or absence of chlorophyll on it.Now iodine is applied to the leaf to test for the presence of starch (starch when ever comes in contact with iodine turns blue).This test shows that only those parts which were prevously green turned blue with iodine while the white parts turned brown. This result indicates that starch is formed only in those parts of the leaf where chlorophyll exists (i.e. green parts). In other words photosynthesis is not possible without chlorophyll. If this were possible the white parts of the laf should have also given a blue colour with iodine.(Diagram) Is Light Necessary for PhotosynthesisExperimentA potted plant is destarched by keeping it in the dark room for two days. It is then transferred to light. Two of its leaves are selected for the examination. One leaf is wrapped completely in black paper. The other leaf is also wrapped in black paper but an L-shaped part of the paper is cut out so that light can reach this part of the leaf through it. The plant is placed in the sunlight for 4 to 6 hours. The two leaves are now detached from the plant and tested for presence of starch. It would be observed that the leaf which does not receive any light is free of starch (remains brown with iodine). However, in the second leaf, light could pass through the L-shaped opening in the black paper. Only this L-shaped area turns dark blue while the other parts of the leaf remain brown. This shows that light plays a vital role in the manufacture of starch since starch is manufactured due to photosynthesis, light is essential for this process.(Diagram) Is Carbon Dioxide Necessary for PhotosynthesisExperimentTwo potted plants are destarched by keeping them in a dark room they are watered properly during this period. Each pot is enclosed in a transparent polythene bag as show in figure. A petri dish containing soda lime (potassium hydroxide) is placed on one of the pots to absorb any carbon dioxide present in the polythene bag. In the other pot a petri dish is placed containing

sodium bi-carbonate solution which would produce carbon dioxide. The plants are then left in light for several hours. A leaf from each pot is detached and tested for starch. The leaf from the pot containing soda lime does not turn blue. soda lime had absorbed any carbon dioxide present in the bag. The leaf from the other pot where carbon dioxide was being released by the sodium bicarbonates solution turns blue indicating the presence of starch. These results show that carbon dioxide is essential for photosynthesis.

Nutrition in ManLike all other animals human beings need food for following activities:1. To get energy this may be used to carry out different activities in the body.2. To build new protoplasm in the cells, renew and replaced damaged cells and tissues for grwoth and reproduction.3. To maintain health and build resistance against various diseases. Man's diet consists of following components:1. Carbohydrates2. Proteins3. Lipids4. Vitamins5. Mineral Salts6. Water

LipidsLipids are obtained from two sources: Animal SourcesGhee, butter, cream, animal fat and fish oil. Plant SourcesOils from mustard, olives, coconut, maize, soya beans, sunflower and peanuts. Importance of Lipids1. The use of fat rich products increase in winters because they provide double the amount of energy as compared to carbohydrates.2. They provide 9000 cal/gm energy to the body.3. In plants fats are stored in seeds, and in animals, they are found beneath the skin and around the kidneys where they are not only stored but also protect these parts.4. They provide materials for building new protoplasm and cell membrane.5. Some fatty acids are essential for man.6. Saturated fats (animal fats) should be used with, great care in our diet as they lead to rise in the cholesterol level, which accumulates in the blood vessels, and thus affects the flow of blood in the arteries This can result in heart attack.

VitaminsVitamins are very complicated compounds. When vitamins were discovered, their chemical nature was not well known. Therefore, they were denoted with English letters as A, B, C, D, E and K. Now it is known that vitamin B is not a single vitamin but a group of vitamins call ed as vitamin B complex. It has eight different compounds as B1, B2 etc although they have no energy value but they are essential in small quantities for the normal activities of life. It has been observed that when animals were given a diet rich in carbohydrates, fats and proteins but lacking

vitamins, the growth and development of the organisms were affected and the animal suffered from various diseases. Vitamins are needed for healthy growth and development of the body. They also serve as enzyme.Plants can prepare their vitamins from simple substances but animals obtain it directly or indirectly from plants. Fifteen or more vitamins have been isolated and most of them seem to act as essential part of coenzyme involved in chemical changes taking place in the body.If our diet has variety and consists of fresh fruit and vegetables, our body will receive all those vitamins which are necessary for us. Fat Soluble VitaminsSome vitamins are fat-soluble and can be stored along with fat. Water Soluble VitaminsSome vitamins are water soluble and hence cannot be stored in the body, thus their in take is required continuously.

Mitosis

It is that cell division in which the number of chromosomes in both daughter nuclei remains same as in parent nucleus.

Events of Mitosis

Mitosis has the following phases: 1. Prophase 2. Metaphase 3. Anaphase 4. Telephase 5. Cytokinesis

Prophase

1. In this phase, coiling of chromosomes starts and their length decreases but diameter increases. It means that chromosomes become shorter and thicker, this process is called condensation. 2. Microtubules arrange to form a structure called spindle. 3. In animal cell, there are also present centrioles on both poles of spindle. From each centriole, small microtubules or fiber arise forming a star shaped aster. 4. Spindle fibers, centrioles and aster collectively form mitotic apparatus. In plants, this apparatus is made up of only spindle fibers as asters are absent in these cells. 5. Nuclear membrane is broken down. Nucleolus disappears and chromosomes scatter over the spindle fiber. 6. Each chromosome consists of two similar threads like structure called chromatids, these chromatids are united to each other by means of centromere.

Metaphase

1. The chromosomes arrange themselves on equator of the spindle to form an equatorial plate. In

this condition, chromosomes become more visible. 2. The chromosomes are attached at their centromere to one spindle fiber from each pole.

Anaphase

1. First of all spindle fibers shrink and become short. 2. The centromere of each chromosome then divides and the two chromatids of each chromosome start separating. At this stage these are not called chromatids because these are no in united condition these are called chromosomes. 3. These chromosomes start moving slowly towards the opposite poles. In this way, one set of chromosomes moves towrds one pole while other towards the other pole.

Telophase

1. The chromosomes reach their poles. 2. The chromosomes uncoil and become less visible. 3. Nuclear membrane reforms and nucleolus appears too. Therefore two nuclei are formed. Each daughter nucleus has the same number of chromosomes as the parent cell.

Cytokinesis

The division of cytoplasm is called cytokinesis. It begins at the last stages of nuclear division. In plant cell, cytoplasm divides by formation of cell plate which is also called phragmoplast. It gradually extends outward and finally two daughter cells are separated. In animals, cytoplasm divides by furrowing. During this, there occurs inward pinching of cell membrane resulting into two daughter cells. In mitosis, two daughter cells are formed from one parent cell which are identical to their parent cell.

Significance of Mitosis

1. Mitosis occurs in all types of somatic cells. 2. Daughter cells formed as a result of mitosis have same number of chromosomes as that of parent cell. In this way, all cells of body of an organism have same number of chromosomes. 3. Zygote divides by mitosis to form embryo and after hatching or birth, mitosis continues up to maturity of an individual. 4. Mitosis also results in growth and repairing of damaged or worn out tissues. 5. Healing of wounds is also due to mitosis. Meiosis

It is that type of cell division in which cytoplasm and nucleus divides twice and as a result of this, four daughter cells are formed and chromosome number is reduced to half. It means that one diploid (2n) parent cell divides to form four haploid (n) daughter cells.

Meiosis consists of two sub divisions: 1. Meiosis I 2. Meiosis II Meiosis I

It has following stages: Prophase I

1. It is lengthy than prophase of mitosis. It is very important phase. It is divided into five stages during which there is continuous condensation of chromosomes. 2. The important process of this phase is synapsis in which homologous chromosomes pair with each other length wise. 3. Each pair consists of four chromatids or two chromosomes. 4. After synapsis, the process of crossing over takes place. In this, homologous chromosomes exchange their chromatids parts at certain places. 5. At end of this phase, nuclear membrane breaks up. Nucleolus disappears and chromosomes scatter over the spindle. 6. Like mitosis, mitotic apparatus is also formed here. (Diagram) Metaphase I

1. The chromosomes arrange on scatter of the spindle. 2. Here, homologous bivalents arrange at equatorial plate of spindle. 3. Only one spindle fiber is attached to each chromosome. Anaphase I

1. Homologous pairs of chromosomes are separated. 2. Spindle fibers contract. 3. Chromosomes begin to move towards the opposite poles. 4. This phase is different from metaphase of mitosis because half the number of chromosomes moves towards each pole and each chromosome still has two chromatids. Telephase I

1. Half the number of chromosomes reach at opposite poles. 2. Chromosomes again increase their length. 3. Nucleolus reappears. Nuclear membrane is reformed and in this way two daughter nuclei are formed. 4. Now cytoplasm divides and two daughter cells are formed. Each cell is haploid (n).

Meiosis II

It is similar to mitosis. The haploid cells formed in meiosis I pass through phases of meiosis II and ultimately four haploid (n) daughter cells are formed. These cells afterwards change into spores (in plants or gametes (animals)

Significance of Meiosis

1. Meiosis takes place only in germ mother cells which form gametes or spores. 2. It maintains the chromosome number of a species constant generation after generation. 3. If gametes had the same number of chromosomes as in somatic cells, the number of chromosomes would have doubled after each generation in a species. 4. The number of chromosomes is constant for each species. During meiosis; gametes (both and) formed are haploid. 5. Gametes unite to form a diploid zygote. 6. During meiosis, pairing of chromosomes takes place which is called synapsis. 7. Exchange of genetic material occurs during meiosis. In this way variations are produced which are raw material for evolution. Discovery of Cells and the Development of Cell Theory

The study of cells started about 330 years ago. Before that time cells escaped notice because of their small size. With the invention of the microscope and its subsequent improvement, cells became visible and many new discoveries were made about them. Even today the study of cells reveals more detail, and its secrets, which are in fact the secrets of life itself, are revealed with ever increasing clarity. 1665: English Scientist and Microscopist Robert Hooke described a honeycomb-like network of cellulae (Latin for little storage rooms) in cork slice using his primitive compound microscope. Robert Hooke used the term cells to describe units in plant tissue (thick cell walls could be observed). Of course he saw only cell walls because cork cells are dead and without protoplasm. He drew the cells he saw and also coined the word cell. The word cell is derived from the latin word cellula which means small compartment. Hooke published his findings in his famous work, Micrographia. Hooke, Robert (1635-1703), English scientist, best known for his sturdy of elasticity. Hooke also made original contributions to many other fields of science. Hooke was born on the Isle of Wight and educated at the University of Oxford. He served as assistant to the English physicist Robert Boyle and assisted him in the construction of the air pump. In 1662 Hooke was appointed curator of experiments of the Royal Society and served in this position until his death. He was elected a fellow of the Royal Society in 1663 and was appointed Gresham Professor of Geometry at Oxford in 1665. After the Great Fire of London in 1666, he was appointed surveyor of London, and he designed many buildings, including Montague House and Dethlehem Hospital. Hooke anticipated some of the most important discoveries and inventions of his time but failed to carry many of them through to completion. He formulated the theory of planetary motion as a problem in mechanics, and grasped, but did not develop mathematically, the fundamental theory on which the English physicist Sir Isaac Newton formulated the law of gravitation. Hooke's most important contributions include the correct formulation of the theory of elasticity, which states that an elastic body stretches in proportion to the force that acts upon it; and analysis of the nature of combustion. He was the first to use the balance spring for the regulation of watches, and devised improvements in pendulum clocks. Hooke was also a poioneer in microscopic research and pulished his observations, which included the discovery of plant cells.

Hooke's Microscope Hooke's drawing of Cork Cells 1670: Antonie van Leeuwenhoek (1632-1723) described cells in a drop of pond water using a microscope. A Dutch businessman and a contemporary of Hooke. He also used microscopes and was a physicist. He made his own fine quality lens for use in monocular microscopes and was the first person to observe bacteria and protozoa. Some of his lenses could magnify objects 250X.Anton van Leeuwenhoek, born Oct. 24, 1632, was a Dutch biologist and microscopist. He became interested in science when, as a Dutch businessman, he began grinding lenses and building simple microscopes as a hobby. Each microscope consisted of a flat brass or copper plate in which a small, single glass lens was mounted. The lens was held up to the eye, and the object to be studied was placed on the head of a movable pin just on the other side of the lens. Leeuwenhoek made over 400 microscopes, many of which still exist. The most powerful of these instruments can magnify objects about 275 times. Although future microscopes were to contain more than one lens (compound microscopes), Leeuwenhock's single lens was ground to such perfection that he was able to make great advances and to draw attention to his field. Leeuwenhoek was the first person to observe single-celled animals (protozoa) with a microscope. He described them in a letter to the Royal Society, which published his detailed pictures in 1683. Leeuwenhoek was also the first person, using a microscope, to observe clearly and to describe red blood cells in humans and other animals, as well as sperm cells. In addition, he studied the structure of plants, the compound eyes of insects, and the life cycles of fleas, aphids, and ants.

Antony van Leeuwenhoek

1833: English Botanist Robert Brown discovered the nucleus in plant cells.

1838: Matthias Jakob Schleiden, a German botanist, concluded that all plant tissues are composed of cells and that an embryonic plant arose from a single cell. He declared that the cell is the basic building block of all plant matter. This statement of Schleiden was the first generalizations concerning cells. Born in Hamburg and educated in law at Heidelberg, Schleiden left law practice to study botany, which he then taught at the University of Jena from 1839 to 1862. A man of disputatious nature he scorned the botanists of his day who limited themselves to merely naming and describing plants. Schlieden investigated plants microscopically and conceived that plants were made up of recongnizable units, or cells. Plant growth, he stated in 1837, came about through the production of new cells, which, he speculated, where prophagates from the nuclei of old cells. Although later discoveries proved him wrong about the role of the nucleus in mitosis, or cell division, his conception of the cell as the common structural unit of plants had the profound effect of shifting scientific attention to living processes as they happened on the cellular level-a change that initiated the field of embryology. A year after Schleiden published his cell theory on plants, his friend Schwann extended it to animals, thereby bringing botany and zoology together under one unifying theory.

Matthias Schleiden1839: Theodor Schwann, a German biologist, reached the same conclusion as Schleiden about animal tissue being composed of cells, ending speculations that plants and animals were fundamentally different in structure. Schwann described cellular strucures in animal cartilage (rigid extracellular matrix). He pulled existing observations together into theory that stated: 1. Cells are organisms and all organisms consist of one or more cells. 2. The cell is the basic unit of structure for all organisms and that plants and animals consist of combinations of these organisms which are arranged in accordance with definite rules. In other words, the cell is the basic unit of life. This statement was the second generalization concerning cells and is the most important in the development of biology. It became known as the cell theory.

Schwann, Theodor (1810-82), German physiologist, generally considered the founder of modern histology, the study of the structure of plant and animal tissues. Schwann was born in Neuss and educated at the universities of Bonn, Warzburg, and Berlin. He was (1838-48) professor of anatomy at the University of Leuven in Belgium; there after until his death he was associated with the University of Libge, also in Belgium, serving as professor of anatomy from 1848 to 1858, when he became professor of physiology. Schwann achieved the physiochemical nature of life by applying the cell theory of the German botanist Matthias Jakob Schleiden to the evolution of animal life. He also demonstrated that the mature tissues of all animals are traceable to embryonic cells. While assisting the German physiologist Johannes Miller in the Anatomical Museum of Berlin, Schwann discovered pepsin, the digestive enzyme, in the stomach epithelium, or membrane tissues, of animals. He also conducted valuable research on the processes of

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fermentation, purefaction, and muscular and arterial contraction. His principal work is Microscopic Investigations on the Accordance in the Structure and Growth of Plants and Animals (1839-1847).

Theodor Schwann

1840: Albrecht von Roelliker realized that sperm cells and egg cells are also cells.

1845 Carl Heinrich Braun Cells were first identified as the basic unit of life

1855: Taking Brown's original description of nuclei and observations by Karl Nägeli on cell division, the German physiologist, physician, pathologist, and anthropologist Rudolf Virchow was able to add a third tenet to the cell theory: Omnis cellula e cellula, or all cells develop only from existing cells.Virchow, Rudolf (1821-1902), German pathologist, archaeologist, and anthropologist, the founder of cellularpathology. Virchow was born in Schivelbein, Pomerania (now Swidwin, Poland), and educated at theUniversity of Berlin. In 1843 he became prosector at the Charite Hospital in Berlin, and in 1847 a university lecturer. In 1849 he was invited to the medical school of Wurzburg as professor of pathological anatomy, having been dismissed from his Berlin posts because of revolutionary activities. In 1856 he returned to Berlin as professor and director of the university's pathological institute.Virchow was the first to demonstrate that the cell theory applies to diseased tissue as well as to healthy tissue-that is, that diseased cells derive from the healthy cells of normal tissue. He did not, however, accept Louis Pasteur's germ theory of disease. He is best known for his text Cellular Pathology as Based on Histology (1850-1860). He engaged also in extensive research in the fields of archaeology and anthropology, producing numerous writings, among them Crania Ethnica Americana (1892). Other publications include discussions of topical political and social questions. Virchow was influential in German politics and from 1880 to 1893 served as a Liberal in the German Reichstag, where he opposed the policies of the German chancellor Prince Otto von Bismarck. He was instrumental in the establishment of the Pathological Institute and Museum in Berlin.

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CHEMICAL COMBINATIONSAND CHEMICAL EQUATION

Laws of Chemical CombinationsThere are four laws of chemical combinations these laws explained the general feature of chemical change. These laws are:1. Law of Conservation of Mass2. Law of Definite Proportions3. Law of Multiple Proportions4. Law Reciprocal Proportions

Antoine Lavoiser has rejected the worn out ideas about the changes that take place during a chemical reaction. He made careful quantitative measurements in chemical reactions and established that mass is neither created nor nor destroyed in a chemical change. Law of Conservation of MassStatementIt is presented by Lavoiser. It is defined as: "Mass is neither created nor destroyed during a chemical reaction but it only changes from one form to another form."In a chemical reaction, reactants are converted to products. But the total mass of the reactants and products remains the same. The following experiment easily proves law of conservation of mass. Practical Verification (Landolt Experiment)German chemist H. Landolt, studied about fifteen different chemical reactions with a great skill, to test the validity of the law of conservation of mass. For this, he took H.shaped tube and filled the two limbs A and B, with silver nitrate (AgNO3) in limb A and Hydrochloric Acid (HCl) in limb B. The tube was sealed so that material could not escape outside. The tube was weighed initially in a vertical position so that the solution should not intermix with each other. The reactant were mixed by inverting and shaking the tube. The tube was weighed after mixing (on the formation of white precipitate of AgCl). He observed that weight remains same. HCl + AgNO3 ----------> AgCl + NaNO3 Law of Definite ProportionsStatementIt is presented by Proust. It is defined as: "When different elements combine to give a pure compound, the ratio between the masses

of these elements will always remain the same." Proust proved experimentally that compound obtained from difference source will always contain same elements combined together in fixed proportions. ExampleWater can be obtained from different sources such as river, ocean, well, canal, tube well, rain or by the chemical combination of hydrogen and oxygen. If different samples of water are analyzed, it will have two elements, hydrogen and oxygen and the ratio between their mass is 1:8. Law of Multiple ProportionsStatementThis law is defined as: "When two elements combine to give more than one compounds, the different masses of one element, which will combine with the fixed mass of other element, will be in simple whole number ratio."Two different elements can combine to form more than one compound. They can do so by combining in different ratios to give different compounds. ExampleHydrogen and oxygen combine with one another to form water (H2O) and hydrogen peroxide (H2O2). In water and hydrogen oxide 2 g of hydrogen combine with 16g and 32g of oxygen respectively. According to law of multiple proportions, the different masses of oxygen (16g and 32g) which have reacted with fixed mass (2g) of hydrogen will have a simple ratio between each other i.e. 16:32 or 1:2. It means that hydrogen peroxide contains double the number of oxygen atoms than water. This law proves this point of Dalton's Atomic Theory that atoms do not break in a chemical reaction. Law of Reciprocal ProportionsStatementThis law is defined as: "When two element A, B combine separately, with the mixed mass of the third element E, the ratio in which these elements combine with E is either the same or simple multiple of the ratio in which A and B combine with each other." ExampleHydrogen and Nitrogen separately combine to form ammonia (NH3) and dinitrogen oxide (N2O), in these compounds, fixed mass of nitrogen is 14g and combines with 8 g of oxygen and 3 g of hydrogen. The ratio between the mass of oxygen and hydrogen is 8:3. Hydrogen and oxygen also combine with one another to form water (H2O). The ratio between hydrogen and oxygen in water is 16:2. These ratios are not same. Let us observe whether these ratios are simple multiple to each other or not following mathematical operation is carried out. 8:3 ::16:28/3 : 16/2or8/3 x 2/16or1/3 => 1:3 DefinitionsAtomic MassThe mass of an atom of the element relative to the mass of some reference or standard element is called atomic mass. Atoms are very small particles. They have very small mass. If the masses of

atoms were to be expressed in gram. It is a very big unit for this very tiny object. Then it was decided by the chemists that masses of the atoms were to be found after comparing with mass to some standard form. Hydrogen being the lightest element is taken as standard. The mass of the hydrogen atom taken as one. The atomic mass could be defined as "Atomic mass of an element is the mass of an atom of that element as compared to the mass of an atom of hydrogen taken as one." ExampleThe atomic mass of sodium is 23. It means that an atom of sodium is 23 times heavier than hydrogen atom. Similarly atomic mass of oxygen is 16. It means that an atom of oxygen is 16 times heaviest than that of hydrogen. AtomThe smallest particle of an element which cannot exist independently and take part in a chemical reaction is known as Atom. ExamplesHexogen(H), Carbon (C), Sodium (Na), Gold (Au) etc. MoleculeThe particle of a substance (Element or Compound) which can exist independently and show all the properties of that substance is called molecule.Atoms of the same or different elements react with each other and form molecule.Atoms of some elements can exist independently, since they have property of molecule so they are called mono atomic molecule. ExamplesExamples of Molecules of the elements are Hydrogen (H2). Nitrogen (N2), Sulphur (S8) etc.Molecules of different elements are called compounds. For example HCl, H2O, CH4 etc. ValencyThe combining capacity of all elements with other elements is called valency. ExampleH = 1C = 4Al = 3Mg = 2Na = 1 __________________CHEMISTRY: INTRODUCTION TO CHEMISTRY

ChemistryThe branch of science which deals with the composition and properties of matter, changes in matter and the laws or principles which govern these changes is called Chemistry. Branches of Chemistry

Physical ChemistryThe branch of chemistry which deals with the physical properties and physical behavior of material things is called physical chemistry. Inorganic Chemistry

The study of all elements and their compounds except carbon is called inorganic chemistry. Organic ChemistryThe branch of chemistry in which we study the compounds of carbon is called organic chemistry.

Analytical ChemistryThe branch of chemistry which discusses the analytical methods for getting information about chemical compounds and chemical processes is called analytical chemistry. BiochemistryThe study of chemical compounds present in living things is called biochemistry. Industrial ChemistryThe application of chemical knowledge in technology and industry and the preparation of industrial products are called industrial chemistry. Steps Involved in Getting Information in the Scientific MethodScience is not only an integrated knowledge of physical and biological phenomena but also the methodology through which this knowledge is gathered. The process of scientific discoveries is a cyclic process.In science the facts are gathered through observations and experiments and then theories or law are deduced. The scientific method include following four steps:1. Observation2. Inference3. Prediction4. Experiment ObservationThe observations are made by the five senses of man. Men made equipments are also used for making observations. For example microscope is used for observing minute objects. Thermometer is used to measure temperature. Sensitive balance is used to determine the mass of a very light object. The capacity of man made instruments is also limited. But it can be improved by improving technology. Thus better and more reliable information are given to the scientists who produce better result. Information acquired through careful observations are called facts. These facts are foundation of scientific knowledge. InferenceThe facts gathered through observations are carefully arranged and properly classified. Correlating the knowledge thus acquired with previous knowledge, we try to think of a tentative solution to explain the observed phenomenon. The tentative solution is called hypothesis. The validity of this hypothesis is tested through the results obtained from experiments. The results are discussed by the scientists and the hypothesis is accepted or rejected. The accepted hypothesis then takes the form of theory. A theory when repeatedly gives the same results after experimentation and gives correct explanation of the scientific facts becomes a law or principle.A theory remains valid until contrary informations are given on the basis of experimentation. Thus a hypothesis requires experimental support. But Avogadro's hypothesis has been accepted as law without any experimental support. PredictionFacts, theories and laws which are deduced from observation can help in deducing more facts and phenomenon. This process is called prediction. ExperimentAn experiment is an integrated activity, which is performed under suitable conditions with

specially designed instruments to get the required information. Such information is used to test the validity of the hypothesis. If a hypothesis is proved correct. It increases the reliability of known facts. If it is proved wrong, it stil can give information which can be used to deduce other results. Chemistry and SocietyChemistry has played important role for well being of mankind in the form of food, clothing, shelter, medical treatment and chemical fertilizers, crops protected by insecticides, refined food and production of artificial fiber. Production of cement, iron bricks, glass, paint etc are all due to chemistry.The hazards of chemistry are so vast that no aspect of human life has remained unaffected. The smoke coming from chimneys of chemial industries and from vehicles pollute the air. It is very dangerous to breath in that air. Similarly waste water from industry, pollute canals, rivers and has bad effect on land. Excessive chemical spray on plants also has bad effect. CLASSIFICATION OF LIVING ORGANISMSClassificationThe arrangement of organisms into groups and subgroups on the basis of similar characters is called classification.

Basis of ClassificationThe classification of organisms is based on such features or characters, which are similar in one kind of organisms and different in different kind of organisms. These characters may be about internal morphology, (anatomy), external morphology, physiology, cell structure, especially the number of chromosomes and chemical composition (especially of proteins) and embryology of the organisms. These characters help in study of intra specific (within the same species) and intra specific (between different) species differences. The presence of similar characters in different organisms indicates their common ancestory. This similarity because of common ancestral origin is called Homology e.g. arm of a monkey, flipper of a whale and wing of a bat show homology. They are dissimilar apparently but their internal structure (arrangement of bones and muscles) is same. These organs are called homologous organs. Due to this homology, we can, say that monkey, whale and bad had common ancestors and are placed in same large group "vertebrate". This homology is proved to be very helpful in classification. Aims/Objectives of ClassificationThese are given below: 1. To determine similarities and differences between different organisms.2. To arrange organisms on the basis of similarities and differences.3. To identify the organisms on the basis of their structure and other prominent characters and study them systematically and logically.4. To find out inter-relationships of organisms. First of all, Aristotle classified the organisms on the basis of their resemblances. After this, Theophrastus classified the plants. Then, after a long time, Carolous Linnaeus (1707-1778), suggested a new system of classification. In this way, he started modem taxonomy. Units of ClassificationThe basic unit of classification is specie (Plural specie). A species is a group of organisms that can breed with one another in nature and produce fertile offspring. All members of a species have same number of chromosomes and also have many other features in common. All the mustard plants belong to one species. All the human beings belong to another species. The

members of one species differ from members of other species and do not breed naturally with each other. Such different species, which are closely related, they are grouped in large group called genus (plural; genera) e.g. Brassica is a genus. It includes several species like mustard, cabbage and turnip. Similarly, Felis is a genus. It includes several species like lion, tiger and cat. Similarly, many closely related genera are placed in a bigger group called Family, families are grouped into an order, orders are grouped into a class and classes are grouped into a phylum (plural, phyla) or division (plural; division) in case of plants. The phyla or divisions are grouped into kingdom. All these units are divided into subunits e.g. sub genus, sub phylum and sub kingdom etc. The smallest the group or unit, the organisms found in this group, would be more similar, they have more number of of similar character.

Difference between Homologous and Analogous OrganismsThe fruit of all plants, whether sweet, or sour, small and dry or large and fleshy, all are the homologous structures because they develop from ovary of flower. Their origin is common. On the other hand, wings of an insect, and a bird, despite having same function, are not homologous because their origin is different. Similarly green leaf of moss plant and that of any vascular plant are not homologous. These organs are similar in function but different in basic structure and origins are called analogous organs. Biological Classification of Mustard PlantCommon Name ----------------- Mustard Phylum or Division ---------- Anthophyta Class ----------------------- Dictyledonae Order ----------------------- Capparales Family ---------------------- Brassicaceae Genus ----------------------- Brassica Species --------------------- Brassica Campestris Classification of Human BeingsCommon Name ---------------- Human Kingdom -------------------- Animalia Phylum --------------------- Chordata Class ---------------------- Mammalia Order ---------------------- Primates Family --------------------- Hominidae Genus ---------------------- Homo Species -------------------- Homo sapiens Scientific Name ------------ Homo sapiens Kingdoms of OrganismsThe classification is not static, nor has only one system of classification been followed rather it is dynamic. Whenever any new knowledge is available about organisms, it is used in classification. Therefore, many systems of classification have been used. Living organisms are classified into two to five kingdoms. Two Kingdom SystemsAll organisms were classified into two kingdoms before present time.1. Plant Kingdom (Plantae) - It includes all the small and large plants.2. Animal Kingdom (Animals) - It includes all the animals. Important Characters of Plants and Animals

Presence of cell wall and ability to prepare their own food were considered the most important characters of plants. Lack of cell wall and inability to prepare food and characteristic mode of nutrition and especially the ability to locomote were considered the most important characters of animals.

Plant kingdom and animal kingdom were divided into large groups. Binomial NomenclatureThe method of giving scientific names to organisms is called nomenclature. Same animal or same plants may be known by different names. It must have one scientific name so that there may be no confusion. To give such names to living organisms, the method was formulated by carolous Linnaeous (1753). This method is called Binomial Nomenclature. Because tis system is simple and comprehensive, so it is accepted and used in whole world.

Rules of Binomial Nomenclature1. According to this method, every species of living organisms is given a Latinized scientific name consisting of two parts.2. The first part is the name of genus and is called generic name. It starts with a capital letter.3. The second part is the name of species and is called specific name. It starts with a small letter.4. Both parts of scientific name of a species are either underlined separately or italicized. The scientific name of mustard plant is Brassica campestris. The scientific name of rose plant is Rose indica. Similarly the scientific name of frog is Rana tigrina and that of human is Homo sapiens. Significance of Binomial NomenclatureBefore establishment of binomial nomenclature, the names of organisms consisted of many words. These words were based on the characters of these plants or animals. In different countries, even in different parts of same country; local names were used for plants and animals. The same organism may be given different names e.g. turnip, shaljam, gongloo, thipar, and gogroon are all names of same plant. In England, there are at least fifty names for pansy. Similarly a single common name may be used for different kind of organisms e.g. the word "raspberry" is used for about 100 kinds of plants. This confusion can be avoided by giving each organism a scientific name according to binomial nomenclature proposed by Carolous Linnaeus in 1753. It is adopted by all taxonomists. Biological Classification of ManCommon Name ----------------- Man Kingdom --------------------- Animalia Phylum ---------------------- Chordata Class ----------------------- Mammalia Order ----------------------- Primates Family ---------------------- Hominidae Genus ----------------------- Homo Species --------------------- Homo sapiens Biological Classification of FrogCommon Name ----------------- Frog Kingdom --------------------- Animalia Phylum ---------------------- Chordata Class ----------------------- Amphibia

Order ----------------------- Salientia (Anura) Family ---------------------- Ranidae Species --------------------- Rana tigrina __________________RESPIRATION

RespirationThe oxidation of the absorbed food material in order to obtain energy is called respiration.There are two types of Respiration in the organisms:1. Anaerobic Respiration2. Aerobic Respiration Aerobic RespirationIn most of the higher and larger organism, the glucose etc is oxidized by using molecular oxygen. This type of respiration is known as Aerobic Respiration. In aerobic respiration a mole of glucose is oxidized completely into carbon dioxide and water releasing enormous amount of energy. One glucose molecule in this respiration produces 686,000 calories of energy. Aerobic respiration thus produces 20 times more energy than the anaerobic respiration.In aerobic respiration food is oxidized in presence of molecular oxygen.

Stages of Aerobic RespirationThere are two stages of Aerobic Respiration: (a) External RespirationIn this stage, the organisms take the air (containing oxygen) into their bodies. This is called external respiration. this stage includes the transport of oxygen obtained from the inhaled oxygen to each cell of the body. (b) Internal RespirationThe second stage is called internal respiration. It consists of the oxidation of glucose, amino acid and fatty acids etc, with molecular oxygen. In this stage all these reactions are included which extract the chemical energy of glucose and other compounds and store it in the form of ATP molecule, this respiration is also called cellular respiration as it occurs within cells.In the internal or cellular respiration glucose and other compounds are passed through such enzymatic reactions which release the chemical energy gradually in small amounts with the help of which ATP molecules are synthesized. Anaerobic RespirationSome organisms oxidize their food without using any molecular oxygen. This is known as Anaerobic Respiration. In this type of respiration considerably less amount of energy is released as compared with the other type of respiration.In anaerobic respiration a glucose molecule is broken down into two molecules of lactic acid with a release of only 47,000 calories of energy. Glucose --------> 2 Lactic Acid + Energy (47,000 calories) Importance of Anaerobic Respiration1. When earth came into being its environment was totally devoid of oxygen. The aerobic organisms cannot lie in anaerobic environment. The early organisms started respiration in the absence of oxygen to produce energy for survival of organisms.2. Some existing organisms like bacteria and parasites which live in oxygen environment have anaerobic respiration.

3. Many useful bacteria and yeasts are anaerobic.4. Even in the aerobic respiration of the first phase is anaerobic. The glycolysis which is the first phase of carbohydrate metabolism involves reaction which does not require the expenditure of molecular oxygen. This proves the idea that aerobic organisms have evolved from anaerobic organisms.5. In our skeletal muscles, although aerobic metabolism takes place but in sustained activity when the oxygen supply cannot keep pace with energy demand, anaerobic respiration supplies the energy continuously by the breakdown of glucose to lactic acid. ATP (Adenosine Triphosphate) It is a chemical compound. ATP is an abbreviation of adenosine triphosphate. Its name indicates that it contains adenosine and three phosphate groups. Adenosine is formed of a nitrogenous base called adenine and a sugar called ribose. In ATP three phosphate groups are attached to the adenosine in a series one after the other. Significance of ATPATP is a big source of energy. The two terminal bonds between the phosphate groups contain large amount of the chemical energy. When these bonds are broken in enzymatic reaction, large amount of energy is released by which energy requiring activities are accomplished, like synthesis of various compounds of carbohydrates, fats, proteins and hormones etc or for carrying out any physical work like muscle contraction, heat production or transport of substances etc.When the terminal bond is broken the ATP is changed into ADP and phosphate 7300 calories of energy are released. Gaseous Exchange in PlantsPlants get their energy from respiration. Plants have no special organ or system fro exchange of gases. The gaseous exchange in plants occurs in cells, of every part of the plant i.e. roots, stems and leaves etc according to their energy demand. The conducting system (xylem and phloem) of plants transports water and nutrients but plays no role in the transport of gases. The air spaces present between the cells of parenchyma of leaves, stem and roots are involved in the gaseous exchange. Gaseous Exchange in Leaves and Young StemsIn the leaves and young stems, gaseous exchange occurs through stomata. Some gaseous exchange also occurs through cuticle. Gaseous Exchange in Woody Stems and RootsIn woody stem and roots, there are present dead cells beneath the epidermis which form cork tissue. Later on, this tissue becomes porous. The pores are called lenticels. These are involved in gaseous exchange. Gaseous Exchange in LeavesThe aquatic parts obtain oxygen for their respiration by diffusion from the dissolved oxygen in water. Whereas the land plants get their oxygen from air directly through their stomata which are more abundant on the lower surface than the upper surface of leaves. Gaseous Exchange in RootsThe roots get their oxygen for gaseous exchange through diffusion from the air existing in the space between soil particles. Process of Respiration in PlantsThe respiration in plants continues day and night. In this process, the oxygen from the airspaces in the leaves and stems is diffused into tissues and cells after getting dissolved in the film of water which is present over the cells. In the cells this oxygen oxidizes the carbohydrates and

other organic compounds into carbon dioxide and water to produce energy. Some of the water (vapours) comes in the airspaces from where they diffuse out to the atmosphere through lenticels and stomata. The elimination of carbon dioxide is more evident from the parts without chlorophyll like growing seeds and buds. The water produced in this process becomes a part of the already present water in the body of plants. The various chemical reactions of respiration are controlled by the specific enzymes. This process occurs at a faster rate in the parts of the plant having rapid growth like growing seeds, buds, apical meristem of roots and shoots, because these parts require more energy to accomplish the growth process. Relationship between Respiration and PhotosynthesisThe gaseous exchange in plant is not very evident during the day time as the products of respiration i.e. carbon dioxide and water are used in the process of photosynthesis. In the bright sunshine, because of high rate of photosynthesis the carbon dioxide produced in respiration falls short and therefore, some carbon dioxide has to be taken into the plant from outside for photosynthesis.In the day time the plants therefore, take in carbon dioxide and expel out oxygen. The process of photosynthesis occurs in chloroplasts whereas the process of respiration takes place in cytoplasm and mitochondria. Gaseous Exchange in AnimalsThe gaseous exchange in different animals takes place by different methods and organs. In unicellular aquatic animals like amoeba, the dissolved oxygen in water diffuses directly through their cell surface into the interior of the animal and the carbon dioxide similarly diffuses out from their bodies into the external water. This is the simplest way of gaseous exchange and it can occur only in small animals with a diameter of less than one millimeter. These animals have greater surface area of volume ratio and have low rate of metabolism. During evolution, as the animals became complex and complex and grew in their size, their skin or external body surface become impervious to water. Thus the gaseous exchange became impossible through diffusion. In large animals certain organs were developed for exchange of gases w.g. the moist vascular skin, gills, lungs and tracheoles. These large animals have developed blood vascular system which transports oxygen from the respiratory surface to the deep cells and tissues in all parts of the body. The blood in all animals has some respiratory pigments like haemoglobin which carry large amount of oxygen efficiently from respiratory surface to the interior cells. Properties of a Respiratory Surface1. Respiratory surface should have large surface area.2. Respiratory surface should be moist.3. Respiratory surface should be thin walled.4. Respiratory surface should have blood supply. Gaseous Exchange Through SkinFor the exchange of gases through the skin the skin must be moist and richly supplied with blood. The oxygen is diffused from the external water to the blood and the carbon dioxide is diffused from the blood to exterior water. In amphibia and fishes the gaseous exchange occurs through the skin besides through the gills or lungs. The frogs and tortoises breath through the skin during their hibernation period. Gaseous Exchange by GillsThe gills are very effective for gaseous exchange in aquatic animals. Gills are of two types:(a) External Gills

(b) Internal Gills (a) External GillsSome animals have external gills which project out of body of animals. These gills have very thin and highly vascularized surfaces e.g. the dermal papillae of star fish and arthropods. (b) Internal Gills These are present inside the body inner to skin e.g. in fishes and arthropods. Have you ever examined a fish closely? How ill you know that the fish is fresh or not? If the colour of gills is red then it is fresh but if the colour of gills is changed, it is definitely not fresh. The red colour of the fish gills shows the presence of oxygenated blood. __________________FOOD AND NUTRITION.

Need for FoodEverything needs energy to do some job e.g. to operate machines, electricity, steam, fuels like coal, petrol, wood etc are burned to get energy. Similarly, living organisms require energy to carry out their diverse activities of life. They maintain the complex structure of cells, excrete waste material, and reproduce for continuation of their race. They grow in size during their life span as they are small when born and are large when adult. A considerable amount of energy is required to carry out the functions of life. The organisms, therefore, need to have some source of energy in order to maintain their life. Organisms get their energy from food. The type of food depends upon the kind of organism using the food. Some organisms use inorganic compounds to get their energy requirements. Some organisms use vegetables (plants) while some others require flesh (animals) as their food.The organisms burn up their food (metabolize) to get a special form of energy called ATP (Adenosine triphosphate) which is used by them to carry out their functions of life.

Nutrients of Food and Their ImportanceThe food of organisms and the organic compounds, building their bodies are almost same. Their bodies are composed of carbohydrates, proteins and fats etc. These substances are used by organisms as their food. They get energy from these substances. They use the components of food in growth and repairing of damaged tissues. Thus substances acquired by organisms to obtain energy are called nutrients and the process by which they are obtained is called nutrition. The food of all organisms which depends upon already prepared food has been found to consist of six basic components. These are as follows:1. Carbohydrates2. Proteins3. Fats, Oils4. Vitamins5. Minerals6. Water

CarbohydratesThey are organic compounds. They are found in all organisms. They are commonly known as sugars. They contain three elements carbon, hydrogen and oxygen in which hydrogen and oxygen exists in 2:1 ratio that is why they are called hydrates of carbon or carbohydrates. One

gram of carbohydrates provides 3800 calories of energy. Forms of CarbohydratesCarbohydrates occur in three forms.1. Monosaccharide2. Disaccharides3. Polysaccharides MonosaccharidesMonosaccharides are simple sugars. Their common example is glucose. Glucose is main source of energy in our body cells. DisaccharidesDisaccharides are formed by condensation of two monosaccharide units e.g. sucrose is formed by the combination of glucose and fructose. Maltose is another disaccharide. PolysaccharidesWhy many monosaccharides link together, they form polysaccharides. A single polyusaccharide may have many hundred units of monosaccharides. The common examples of polysaccharides are glycogen and starch. Glycogen occurs in animals and starch in plants. Another polysaccharide is cellulose, present in the cell walls of plants. It is the most abundantly occurring carbohydrate. Sources of CarbohydratesCarbohydrates containing starch are obtained from cereals and their products like wheat, rice, maize, oats and barley. They are also obtained from carrots, radish, turnip, beet, beet root and potatoes. Simple sugar called glucose is obtained from grapes. The sugar derived from fruit is called fructose. Then from beet and sugar cane is called sucrose and that from milk is lactose. Importance of Carbohydrates in Human BodyOne gram carbohydrate food provides 3800 calories to our body. The Carbohydrates are the cheapest and easy source of energy. Surplus carbohydrates are stored as glycogen in the liver and muscles, or converted to fats and stored in the fat cells beneath the skin and causes obesity.Children, laborers and people, involved in physical labor need more carbohydrates in their daily diet whereas other should avoid them because their excess in the body can cause blood pressure, diabetes, obesity and heart diseases, therefore, carbohydrate products should be taken with care.

ProteinsProteins are very important organic compounds found in all organisms. Proteins contain carbon, hydrogen, oxygen and nitrogen and sometimes some amount of sulphur. There is no 2:1 ratio between hydrogen and oxygen. A protein molecule is composed of many building units linked together to form a chain. A chain of amino acids is called polypeptide. Amino acids are building units of a protein molecule. About twenty different amino acids occur in nature that combines in different manners to make different type of proteins. Proteins are structural part of the cell membrane. Some proteins are fibrous. They form different structures in the body like muscles, bones and skin. They also occur in our blood and cells. The enzymes which control different chemical reactions in the body are also proteins in nature. As a result of protein catabolism, energy is released. One gram of protein produces 4.3 kilo cal of energy which is used to synthesize ATP. Amino AcidsPlants can synthesize all the amino acids they need from carbohydrates, nitrates and sulphates but animals can not synthesize all amino acids. Amino acids are the building units of proteins.There are about twenty different types of amino acids which are used in the synthesis of protein

found in the human body. Non-Essential Amino AcidsThere are many amino acids which a human body can synthesize within the body. These are called non-essential amino acids. Essential Amino AcidsThere are approximately ten amino acids, which human beings cannot make. These are called essential amino acids and can be obtained directly from proteins in the diet. Sources of ProteinsFollowing are the sources of proteins:Animal Sources e.g. meat, fish, chicken, milk and cheese. Plant Sources e.g. legumes, pulses, dry fruit and cereals. Importance of Proteins in Human Body1. Proteins are essentially required for growth and development.2. Growing children ,pregnant women and lactating mothers need a lot of proteins.3. An adult requires 50-100 gms of proteins daily.4. Protein deficiency in children and cause a disease called Kwashiorkor.5. Proteins play an important role in the building of cellular protoplasm.6. They also play an important role in the building of muscles and connective tissues.7. Many proteins are required for making enzymes, hormones and antibodies.8. If proteins are eaten in excess than needed by body, the excessive amino acids are converted into carbohydrates by the liver, which are either oxidized to release energy and converted into glycogen and fat and stored.

Fats and OilsThey are also organic compounds found in plants, animals and humans. They are very important compounds made up of carbon, hydrogen and oxygen. Fats contain more carbon and hydrogen as compared to oxygen. A fat molecule has two parts, glycerol and fatty acids. Fatty AcidsDifferent kinds of fats contain different fatty acids. Fatty acids are basically of followin two types:1. Unsaturated Fatty Acids2. Saturated Fatty AcidsUnsaturated fatty acids (molecules with one or more than one double bonds) are liquids at room temperature and are called oils. These are good for human health. Saturated fatty acids (molecules without double bond) are solid at room temperature and are called fat. They are not good for human health because they increase cholesterol level in the body. They cause narrowing of blood vessels which may result in heart attack. Vegetable SourcesVegetable fats are liquid and are called oils e.g. mustard oil, olive oil, coconut oil, corn oil. etc. Animal SourcesAnimal fats are solids e.g. butter, ghee and fatty meat. Source of EnergyFats and oils are rich source of energy they provide double energy as compared to carbohydrates and proteins. One gram of fat on oxidation releases 9.1 kilo cal of energy to make ATP.

Photosynthesis

Photosynthesis is a Latin word derived from two words photo (light) synthesis (building up). In this process, green plants manufacture carbohydrates from carbon dioxide and water. The energy needed for this process is obtained from sunlight, which is absorbed by chlorophyll and oxygen is produced as by-product. Leaves are the major sites of photosynthesis in most plants but all green parts of a plant including green stems; un-ripened fruit can carry out photosynthesis. Temperature also plays a very important role in photosynthesis. Temperature affects the rate of photosynthesis. This process occurs during day time only. Conditions and Factors Necessary for PhotosynthesisWaterPlants need water for many functions of life. Water enters the root hair from the soil. It passes through various cells and reaches the xylem of the root. From here it moves to the stem and then the veins of the leaves. Finally, it reaches the mesophyll cells in the leaves. It provides hydrogen for the synthesis of glucose and helps in opening and closing of stomata. If leaves get less water, less stomata open, this reduces the rate of photosynthesis. Opening of more stomata provide more carbon dioxide for photosynthesis. Carbon DioxideThis is an important factor which affects photosynthesis. The amount of carbon dioxide in the atmosphere is about 0.03% and does not vary much. Its amount differs from place to place which may affect the rate of photosynthesis. e.g. the concentration of carbon dioxide close to the ground in a dense forest is higher than in an open field. Although carbon dioxide is needed in very little amount by the plants, yet photosynthesis cannot take place without it. It diffuses from the air into the intercellular spaces through stomata and enters the chloroplasts in the mesophyll cells. Carbon dioxide provides carbon to build up glucose molecule. If the amount of carbon dioxide in the atmosphere increases to 1% rate of photosynthesis also increases, and it starts decreasing if concentration of carbon dioxide is decreased. If the concentration of carbon dioxide decreases below 0.03% the rate of photosynthesis also declines. ChlorophyllIt is the green substance. It is found in special organelles called chloroplasts, which are found in the green leaves and herbaceous stems. In leaves, it is present in the mesophyll cells. Chlorophyll changes light energy into chemical energy and makes food in plants. Plants lacking chlorophyll cannot carry out photosynthesis occurs only in those parts where chlorophyll is present. SunlightLight is very important for the process of photosynthesis. Without light the photosynthesis cannot take place. It provides energy needed for the synthesis of glucose molecule. Light intensity varies from day to day and from place to place. Plants photosynthesize faster on a bright sunny day than on a cloudy day. While light consists of seven colours. The blue and red are best for photosynthesis. Is Chlorophyll Necessary for Photosynthesis?ExperimentSince it is not possible to remove chlorophyll from a leaf without killing it, so it becomes necessary to use a leaf where chlorophyll is present only in patches. Such a leaf is known as variegated leaf and a plant with such leaves is used in this experiment.For destarching the leaves, the pot is kept in a dark place for a couple of days and then exposed to day light for a few hours. The leaf is then removed from plant. Its outline is carefully drawn to note the position of presence or absence of chlorophyll on it.Now iodine is applied to the leaf to test for the presence of starch (starch when ever comes in

contact with iodine turns blue).This test shows that only those parts which were prevously green turned blue with iodine while the white parts turned brown. This result indicates that starch is formed only in those parts of the leaf where chlorophyll exists (i.e. green parts). In other words photosynthesis is not possible without chlorophyll. If this were possible the white parts of the laf should have also given a blue colour with iodine.(Diagram) Is Light Necessary for PhotosynthesisExperimentA potted plant is destarched by keeping it in the dark room for two days. It is then transferred to light. Two of its leaves are selected for the examination. One leaf is wrapped completely in black paper. The other leaf is also wrapped in black paper but an L-shaped part of the paper is cut out so that light can reach this part of the leaf through it. The plant is placed in the sunlight for 4 to 6 hours. The two leaves are now detached from the plant and tested for presence of starch. It would be observed that the leaf which does not receive any light is free of starch (remains brown with iodine). However, in the second leaf, light could pass through the L-shaped opening in the black paper. Only this L-shaped area turns dark blue while the other parts of the leaf remain brown. This shows that light plays a vital role in the manufacture of starch since starch is manufactured due to photosynthesis, light is essential for this process.(Diagram) Is Carbon Dioxide Necessary for PhotosynthesisExperimentTwo potted plants are destarched by keeping them in a dark room they are watered properly during this period. Each pot is enclosed in a transparent polythene bag as show in figure. A petri dish containing soda lime (potassium hydroxide) is placed on one of the pots to absorb any carbon dioxide present in the polythene bag. In the other pot a petri dish is placed containing sodium bi-carbonate solution which would produce carbon dioxide. The plants are then left in light for several hours. A leaf from each pot is detached and tested for starch. The leaf from the pot containing soda lime does not turn blue. soda lime had absorbed any carbon dioxide present in the bag. The leaf from the other pot where carbon dioxide was being released by the sodium bicarbonates solution turns blue indicating the presence of starch. These results show that carbon dioxide is essential for photosynthesis.

Nutrition in ManLike all other animals human beings need food for following activities:1. To get energy this may be used to carry out different activities in the body.2. To build new protoplasm in the cells, renew and replaced damaged cells and tissues for grwoth and reproduction.3. To maintain health and build resistance against various diseases. Man's diet consists of following components:1. Carbohydrates2. Proteins3. Lipids4. Vitamins5. Mineral Salts6. Water

LipidsLipids are obtained from two sources: Animal SourcesGhee, butter, cream, animal fat and fish oil. Plant SourcesOils from mustard, olives, coconut, maize, soya beans, sunflower and peanuts. Importance of Lipids1. The use of fat rich products increase in winters because they provide double the amount of energy as compared to carbohydrates.2. They provide 9000 cal/gm energy to the body.3. In plants fats are stored in seeds, and in animals, they are found beneath the skin and around the kidneys where they are not only stored but also protect these parts.4. They provide materials for building new protoplasm and cell membrane.5. Some fatty acids are essential for man.6. Saturated fats (animal fats) should be used with, great care in our diet as they lead to rise in the cholesterol level, which accumulates in the blood vessels, and thus affects the flow of blood in the arteries This can result in heart attack.

VitaminsVitamins are very complicated compounds. When vitamins were discovered, their chemical nature was not well known. Therefore, they were denoted with English letters as A, B, C, D, E and K. Now it is known that vitamin B is not a single vitamin but a group of vitamins call ed as vitamin B complex. It has eight different compounds as B1, B2 etc although they have no energy value but they are essential in small quantities for the normal activities of life. It has been observed that when animals were given a diet rich in carbohydrates, fats and proteins but lacking vitamins, the growth and development of the organisms were affected and the animal suffered from various diseases. Vitamins are needed for healthy growth and development of the body. They also serve as enzyme.Plants can prepare their vitamins from simple substances but animals obtain it directly or indirectly from plants. Fifteen or more vitamins have been isolated and most of them seem to act as essential part of coenzyme involved in chemical changes taking place in the body.If our diet has variety and consists of fresh fruit and vegetables, our body will receive all those vitamins which are necessary for us. Fat Soluble VitaminsSome vitamins are fat-soluble and can be stored along with fat. Water Soluble VitaminsSome vitamins are water soluble and hence cannot be stored in the body, thus their in take is required continuously. CHORDATA AND VERTEBRATE.

Characters of Class Pisces (fishes)1. The class of fishes is called Pisces. They are aquatic vertebrates.2. According to their size and shape, the fishes are of many kinds.3. They have a head, a trunk and a tail.4. The head and trunk are directly jointed together and neck absent.

5. Body of fish is flexible tapering at both ends and streamlined. This type of body helps in swimming.6. They can swim with fins, which are attached to the trunk.7. They body is covered with scales which remain moist by special type of secretion of body.8. Breathing organs are gills which are present in the hollow spaces found on both sides of the head for exchange of gases i.e. oxygen and carbon dioxide.

9. Mouth has teeth, which is used for grasping instead of grinding of food.10. In some fishes air pouch is present, which is called air bladder. The air bladder is used for buoyancy. Class Amphibia1. This group of animals can live both in water and on land.2. They need water for reproduction. Therefore they are called Amphibians.3. The skin is thin, moist and slimy.4. Small teeth are present in the upper jaw which is only used for grasping the prey.5. Breathing organs are two lungs. Skin is also used for the exchange of gases.6. Eggs are laid in water or moist places and their outer shells are not hard.7. They are cold blooded animals e.g. they cannot maintain their body temperature constant.8. They become very slow and bury themselves in the mud. This process is called hibernation.9. During the process of reproduction fertilized egg is changed into adult passing through a number of physical changes. This process is called metamorphosis.10.The fertilized egg develops into larva. The larva of frog is called Tadpole. It has tail and gills. This larva later changes into adult. Class ReptiliaThe animals of this class are called reptiles. They have following features. Reptiles1. Most of the reptiles are terrestrial and only a few five in water.2. They are also called crawlers.3. They have thick, dry and rough skin.4. The skin is covered with scales which originate from the ectoderm.5. There are present lungs for respiration.6. Teeth are present in their buccal cavity, which are used for cutting and biting.7. The locomotary organs are legs but snakes and a few types of lizards have no legs.8. Most of the lizards are not poisonous except members of the genus Heloderma which are found in American desert.9. All the reptiles lay their eggs on land. Water dwelling reptiles e.g. turtle also lay their eggs on land.10. Their eggs have a tough outer shell of calcium carbonate. Class AvesThe animals included in this class are called Birds. Their distinguishing characters are as follows.

1. Birds have a single unique feature, which makes them different from other animals which is the presence of feathers. Their forelimbs are modified to form wings while hind limbs help in walking, wading and sitting on the branches.2. All the birds have horny beaks without teeth.3. All the birds lay eggs.

4. All the birds must have two wings for support and propulsion, strong but light and hollow bones.5. Their digestive system is able to digest high caloric food.6. They have a higher blood pressure and higher metabolic rate.7. Nervous system and especially eye sight is very well developed so that they can track their path even at a very high speed.8. They migrate during winters towards warmer places covering thousands of miles.9. It is the most studied and most observable class in the world.10. The birds are very beautiful and have melodious voices. Types or Groups of BirdsRunning Birds (Ratitae)They have following characters:1. They have flattened sternum.2. Their pectoral muscles are weak.3. Their examples are Ostrich, Emu, Rhea and Casso wary. Flying Birds (Carinatae)They have following characters:1. A keel is present on sternum in these birds.2. Keel is vertical bony part that is present below the sternum in the centre from anterior to posterior end.3. Pectoral muscles are very strong, powerful and are inserted on the keel. These muscles help them to fly.4. Their common examples are pigeon, hen, crow, kite etc. Class MammaliaAll the animals included in this class are called "mammals". These animals are highly advanced vertebrates. There are almost four thousand species of mammals including man. Characteristics of MammalsTheir distinguishing characters are given below: HairThe body of mammals is covered with hair. In most of the mammals hair may cover the whole body but in a few may be restricted to some areas. The hair conserves heat of the body. GlandsTheir skin is provided with sweet glands, scent glands, sebaccous glands and mammary glands. SkeletonTwo occipital condyles, secondary bony palate, three bones in middle ear and fused pelvic bones and seven cervical vertebrae are present in their skeleton. External EarFleshy external ears are present in mammals. EyelidsMoveable eyelids are present in mammals. TeethTwo sets of teeth are present. Milk teeth are replaced by permanent set of teeth. BrainBrain is higly developed. It perform more functions than that of other vertebrates. Cranial NervesTwelve pairs of cranial nerves are present.

Circulatory SystemCirculatory system has four chambered heart, persistent left aorta and non-nucleated biconcave red blood corpuscles are present in female. ***es***es are separate i.e. there are two individuals, male and female. FertilizationMost of them have internal fertilization and fetus developed inside the uterus of female giving birth to their children. Breast FeedingThey feed the children by milk from mammary glands. EndothermicThey are endothermic i.e. they can maintain their body temperature according to the environment. It means that they are warm-blooded animals. Egg Laying MammalsThese mammals lay eggs. Mostly two eggs are laid in one year. Fertilization of egg is internal i.e. inside the body of mother. Eggs are laid in burrows of animals. Young ones are hatched from the eggs. Mother feed their children with milk. Their egg laying character shows their relationship with reptiles. Duck bill platypus and Spiny ant eater are the examples of egg laying mammals. Pouched Mammals or Marsupial MammalsThese mammals have a pouch outside the belly called marsupium, this is the reason that they are also known as Marsupial mammals.1. Fertilization of eggs and development of embryo is internal.2. The embryo is at first encapsulated by shell membrane and floats free for several days in the uterine fluid.3. There is no placenta.4. After hatching from the shell membranes, the embryo does not implant or "take root" in the uterus and absorb nutrient secretions from the vascularized yolk sac.5. The gestation period is brief and the marsupials give birth to tiny young that is effectively still an embryo.6. These young creeps into the marsupium where it gets milk from mother through nipple.7. It lives in marsupium until it can take care of itself.8. Examples are Kangaroo, Koala, Tasmanian wolf and Wombat etc. These are found in Australia and Tasmania, Opossum is found in America. It lives on trees. Placental MammalsThis is common group of mammals in which embryo completes its development inside the mother's uterus. After gestation period young ones are born. Embryo remains in the uterus and gets its nourishment from mother through umbilical cord and placenta. Gestation period of these mammals is longer than those of other mammals. Pregnancy is called Gestation Period. In man it is of 9th months.In mice it is 21 days, in rabbit 30 to 36 days, in cats and dogs 60 days, in cattle 250 days and in elephants 22 months. It is lengthier in large mammals.The conditions of young ones at time of birth are different in different mammals. For example in antelope, at the time of birth, the body of young is covered over, with heavy fur, eyes are open and it can walk about. In case of rat, young is very weak, eyes are closed and has no hair on the body.

Flora and Fauna of PakistanFloraDefinition"Different types of plans present in a particular region constitute its flora." Details1. Hilly regions of Pakistan have snow fall and low temperature. These regions have thick forests where trees of Juniper (Sanober), Cedar, Chir, Chalghoza, Olive Apple, Plum Peach and Loqaut are very common.2. Plain areas of Pakistan have fertile and less fertile soils. In areas where rainfall is low, desert environment is present in which Aeacia (Babool), Kikar, Ber, Pilas etc grow.3. Fertile plains have trees of Sheesham, Bakain, Cane, Bamboo and Eucalyptus. These are source of timber whereas; fruit trees include mango, banana, Kino, Orange, Grapes, Jamman etc.4. Plain and hilly areas have natural pasture lands that provide fodder for cattle.5. In sea, rivers, ponds, canals and streams, algae are abundant, which on one hand are the source of food for aquatic animals and on the other hand they provide oxygen to atmosphere.6. A large number of plants are used as ornamental plants. These include flowering plants like rose, motia, jasmine, lady of night, chrysanthemum etc.7. Besides this wheat, maize, rice, oats, burley, grams garlic, onion, potatoes, carrots, cabbage and turnips etc are cultivated in plains and hilly areas to meet our food requirements. FaunaDefinition"Different kinds of animals present in a particular region are known as its Fauna." Detail1. In the seas adjoining our coastal areas numerous types of animals are found starting from protozoa to mammals. The most noticeable are octopus, mussels, star fish, sea urchins, crabs, prawns, fishes, amphibians, whale, dolphin etc.2. Many animals are used as food e.g. prawns, crabs and fish etc. Our rivers are rich in fish life particularly Rohu, Khagga, Malhi, Trout, and carps are abundant and used as human food, as well as a source of earning lively hood.3. Frogs and toads are abundant.4. The tortoises, turtles, snakes, crocodiles are also common.5. On the plains of Pakistan we have very rich wild life. There is a great diversity of land fauna starting from earthworms, almost all kinds of insects, spiders, myriapods, snails, slugs to toads, lizards, snakes and enormous variety of birds and mammals.6. Some of the birds peculiar to Pakistan are Houbara bustard, partridge, pheasant, falcons etc.7. The mammals peculiar to Pakistan include Black buck, Blue ball, Brown bear, Musk deer, Urial, Ibex, Asiatic ass.etc.8. Most of the animals provide milk, meat, hide and wool. Some are used for transportation. Some of the animals are now endemgered species because of their excessive hunting and pollution. WARM BLOODED ANIMALSThe animals which do not change their body temperature with the change of temperature in environment are called as Warm Blooded Animals. Their body temperature remains constant.ExampleCommon examples of warm blooded animals are following.(i) Parrot

(ii) Sparrow(iii) Pigeon(iv) Ostrich(v) Kiwi(vi) Duck billed platypus(vii) Kangaro(viii) Oppossum(ix) Elephant(x) Whale(xi) Monkey(xii) Man COLD BLOODED ANIMALSThe animals in which the body temperature is changed with the changes of temperature in the environment are called Cold Blooded Animals.ExampleCommon example of cold blooded animals are following.(i) Shark(ii) Labeo (Rohu)(iii) Trout(iv) Hilsa (Pullah Fish)(v) Cat Fish (Khagga)(vi) Frog(vii) Toad(viii) Snake(ix) Wall-Lizard(x) Crocodile INVERTEBRATE. Protozoa1. According to two-kingdom classification, protozoa are the first phylum of invertebrate animals but according to five kingdom classification it is placed in a separate kingdom, "protista" in which all other eukaryotic unicellular organisms are also placed.

2. Body of all protozoans consists of one cell and istherefore called unicellular.3. They are so small in size that they cannot be seen with naked eye. They can be seen with the help of a microscope.

4. They are unicellular but they intake food, respire, reproduce.5. Protozoans mostly live in damp, watery places. Their habitat is mostly moist soil, decaying matter of animals and plants. Most of them live singly but some form colonies. In a colony, unicellular organisms become partially interdependent and limit themselves to perform specific functions in a group. If separated from group they still can perform all life activities and can live independently.6. Some protozoans are parasites and causes different diseases e.g. a type of Amoeba causes dysentery, plasmodium causes malaria.7. Protozoans are also useful for man because they feed and destroy bacteria which are harmful for human health, for example Amoeba can feed on bacteria. Paramecium

It is unicellular animal which is found in pools and ponds. It is slipper shaped its body is covered with cilia. Cilia are small hair like out structures arising from protoplasm. Their lashing movement in water acts as oars and help in swimming (locomotion) of the animal. Paramecium feed on algae. Bacteria and other small protozoans, through an oral groove provided with cilia. Cilia push food inside the protoplasm through a canal called gullet making a food vacuole in the protoplasm. There are two contractile vacuoles, one at each end of the body for discharging surplus water there are two nuclei one large, mega nucleus which controls almost all functions of cell other small, micro or reproductive nucleus which controls reproduction. Many protozoa like Amoeba and Paramecium are unicellular but they respond to the intensity of light like all other multicellular organisms. They can detect high intensity of light and move towards the area having low intensity of light. Phylum Porifera1. This phylum is called porifera because animals belonging to this phylum have numerous small pores on their bodies.2. They are also called sponges.3. They are multicellular but they have no organs or true tissues.4. Every cell performs its all function.5. Sponges are aquatic animals. Most of them are found in sea water but some live in fresh water.6. Sponges have different colours.7. Green colour of sponge is due to algae that live in their body. Algae produce oxygen during photosynthesis which is used by sponges and the sponges release carbondioxide, which is used by algae for photosynthesis. This association in which both the organisms benefit from each other is called mutualism. Phylum Cnidaria1. Animals belonging to this phylum have a special cavity in their body which is called coelenteron and due to this reason they are called coelenterates.2. They are diploblastic animals as their bodies have two layers of cells. Outer layer is called ectoderm and inner layer is called endoderm. Between these layers a jelly like substance the mesoglea is present.3. Coelentrates are aquatic animals. They are mostly marine but few live in fresh water.4. Most of the animals of this phylum can move freely but a few remain attached to stones or rocks throughout their life.5. Hydra, Jellyfish and Sea anemone are common examples of this phylum. Phylum PlatyhelminthesThey are triploblastic animals because their body is made of three layers, an outer ectoderm, a middle mesoderm and an inner endoderm layer. They are also called flat worms because their body is thin, flattened and tape like. Some animals are free living but most are parasite. Parasites live in liver, stomach and intestine of other animals. They attach themselves to the walls of intestine of their host by ****er and **** blood and food. Tape worm ****s food from intestine and sometimes grows up to 40 feet in length. Liver fluke, tape worm and planaria are common examples of this phylum. Phylum Mollusca1. This phylum is one of the largest phyla of animal kingdom. It has about fifty thousand species.2. Mollusca are a latin word which means "soft". Their body is soft so in most of the animals and external shell is present for support and protection.3. Some animals have internal shell and some lack shell. They are also known as shell fish.

4. They are found in aquatic and moist habitat.5. Most of Mollusca are used as human food.6. Buttons are made from their shell.7. The pearls are produced by these animals.8. Their body is quite complicated.9. They have a muscular foot for locomotion and gills for respiration.10. Snails, Fresh water mussel, Cuttle fish, Octopus and Oyster are common examples of this phylum. Phylum Arthropoda1. The bodies of these animals are also segmented but these segments are external.2. Their bodies are covered with the hard shell composed of chitin, forming an exoskeleton.3. They have jointed legs on their body and therefore they are called arthropoda (arthro means jointed and poda means foot)4. These animals are found in all habitats, in air, water and on land.5. Common examples are Prawn, Crab, Spider, Scorpion, Centipede, Millipede and Insects. Phylum Echinodermata1. The animals of this phylum are exclusively marine.2. They are called echinoderms because their bodies are covered with spines or spicules.3. All animals have internal skeleton consisting of dermal caleareous ossicles.4. They have a water vascular system and dermal gills.5. These animals are considered to be closest to the chordates from evolutionary point of view, Sea star (known as star fish). Brittle star, Sea urchin and Sea cucumber are examples of this phylum. Phylum Annelida1. Animals in this group have elongated segmental body.2. Annelids occur in water as well as on land.3. They have well developed systems in their bodies.4. They have close type circulatory system. Phylum Nematode1. Nematodes or round worms have long smooth cylindrical body which is pointed at both the ends.2. The body is un-segmented.3. Nematodes have a complete and one way digested tube.4. They are free-living as well as parasites of animals, man and even plants. FUNGI AND ALGAE.FungiDuring rainy season, a large number of umbrella-shaped mushrooms emerge on dung-piles. Fluffy mass of tangled threads like structure with black-dots of molds is also often seen growing on orages and bread, these mushrooms and molds are fungi.Characteristics of Fungi1. Fungi are simple heterotrophic eukaryotes which cannot manufacture their food and have absorptive mode of nutrition (e.g. absorbed prepared food).2. Cell wall is made up of Chitin instead of cellulose.3. Some fungi are parasitic while others are saprotrophs.4. Parasitic fungi obtain their food from other living organisms.5. Saprotrophic fungi get their food from dead animals, plants, their wastes and decaying

materials.

Economic Importance of FungiFungi are useful as well as harmful to humans. e.g. Useful Aspects of FungiSaprotrophic FungiSaprotrophic fungi chemically break down dead bodies of organisms and their wastes into simple components. They clean the environment and also cause the recycling of nutrients. Mycorrhizal FungiMycorrhizal fungi improve the growth production of crop plants. Edible FungiMushrooms and some other fungi are edible. AntibioticsSome antibiotics are also obtained from some fungi. For example, Penicillin, the first antibiotic discovered in 1928 by Alexander Flemming. Penicillin is obtained from the fungus penicillium. YeastsYeasts are used in making bread and alcohol. Mushroom1. During rainy season, a large number of umbrella like mushrooms emerge on dung piles.2. Mycelium of mushroom is saprotrophic, spreading under group in the soil that contains, decaying and organic matter.3. When spores are to be formed, many hyphae of mycelium come out of the soil to form umbrella shaped fruit bod, the familiar mushroom. It can be 3,4 inches in height.4. Fruid body consists of two main parts; a lower stalk or stripe, and an upper umbrella shaped cap or pilens which bears annulus around it just below the cap.5. On maturation, many radial plates or gills are seen on the underside of the cap on which enormous numbers of spores are produced.6. Some mushrooms, like Agaricus, can be used as food before their fruit bodies become overripe. Agaricus is rich in protein. Some mushrooms, like Amanita, are deadly poisonous.

AlgaeAlgae are a group of simple eukaryotes in which, like plants, chlorophyll is found. They are photosynthetic autotrophs and have cellulose in their cell wall. However unlike plants but ike fungi, their organs are unicellular and body is simple, thallus. Therefore they are placed in another kingdom, the Protista.Algae, are mostly (found in water). A large number of algae are found in vast saltwater oceans. These are called marine algae, other are found in lakes, ponds, puddles, streams and rivers. These are called fresh water algae. Some marine algae, called the helps and grow as long as 60 meters or more in a season. Some of them are used as food. Characteristics of Algae1. All the algae have chlorophyll so they are autotrophic; they make their own food by photosynthesis.2. Their cell walls are made up of cellulose.3. Algae are mostly marine found in the sea. While others are found in fresh water lakes, ponds, puddles, streams and rivers and they are also found in damp soil.4. Their plant body is called a thallus without a true root, stem or leaf.5. Algae are sometimes

classified on the basis of the pigments they contain. Their green colour can be masked by the presence of other pigments.6. Their reserved food material is starch.7. Algae have a wide variety from unicellular algae, e.g. chlamydomanas and spirogyra to multicellular large seaweeds like sargassum.8. Previously algae were regarded as plants and were placed in thallophyta. ChlamydomonasIt is fresh water green alga, commonly found in fresh pond and drains. It is single celled green algae which are seen only under a microscope.Structure1. Chlamydomonas is spherical, oval or pear-shaped.2. The cell is enclosed by a cell wall which maintains its shape.3. In the anterior part, the cell wall forms an outgrowth called apical papilla.4. Two flagella (singular flagellum) arise from the cytomplasm below the apical papilla and come out through the cell wall. These help in swimming.5. A thin cell membrane lies beneath the cell wall, it represents the ourter surface of cytoplasm.6. In cytoplasm, there is, a cup shaped chloroplast, which is involved in production of food by process of photosynthesis.7. The chloroplast contains, a spherical structure called pyrenoid in its posterior part, and a single red orange light-sensitive eye-spot on one side in its anterior regions.8. The pyrenoid is supposed to store carbohydrates in the form of starch grains. 9. The eye spot helps chlamydomonas to determine its position nd direction according to changes in the intensity of light.10.There are two contractile vacuoles near the base of flagella 'which periodically expel excess water and waste from the cell.11.A nucleus is present in the middle of chloroplast in the cytoplasm.12.Although body, of chlamydomonas consists of a single cell, yet it performs all the basic functions of life. It reproduces both *** and a***ual.(Diagram) Spirogyra1. Spirogyra is a multicultural filamentous green alga. It is found in great abundance in fresh water ponds, lakes and streams. Its filamentous thallus consists of cylindrical cells.2. These cells are joined end to end, to form un-branched filaments. Usually the filaments are found occurring in a large number.3. The filaments are surrounded by a layer of mucilage that makes them slippery.4. During day time, the oxygen produced during photosynthesis stores in the mucilage and the filaments start floating on the surface of water.5. Each cell of Spirogyra is usually twice as long as broad.6. The cell is surrounded by cellulosic cell wall. A peripheral layer of cytoplsm is present just inside the cell wall and around a large, central vacuole.7. The vacuole is filled with cell sap.8. A single nucleus is suspended near the vacuole by cytoplasmic strand.9. The most prominent part of cell is its chloroplast. There may be one ore more than one chlrorplasts in each cell. The chloroplasts run along the; length of the cell in the form of spiral ribbon in the peripheral cytoplasm.10. Numerous pyrenoids are located in a row in the chloroplast and are meant for storing starch.

Spirogyra continually grows in length by cell division.11. Each cell can be divide into two, so filament increases in length. The Spirogyra reproduces both ***ually and a***ually. VIRUS, BACTERIA AND CYANO BACTERIA.

Micro-OrganismsA large number of living things are present in this world. Some of them are large and some are small. Majority of the organisms are so small that they re not seen with naked eyes. For their observation, we need a light microscope or even an electron microscope. These microscopic organisms are called micro-organisms. Micro-organisms As a Heterogeneous GroupMicro-organisms are a heterogeneous group. It includes different kinds of organism viruses, bacteria, cyanobacteria, protozoa, certain algae and some fungi. On the basis of structure they range from sub-cellular to cellular for example, viruses are sub-cellular and all other micro-organisms are cellular. Bacteria, and cyanobacteria are prokaryotes (without nucleus) where as algae, fungi and protozoa are eukaryotes (with nucleus). On the basis of mode of nutrition algae are autotrophic while fungi and protozoa are heterotrohic. Therefore, micro-organisms differ in their structure and mode of characteristics of viruses, they are studied in a separate group where as bacteria and cyanobacteria, being prokaryotes, are included in kingdom Monera. Viruses1. Virus is a Latin word which means "Poison". Viruses are so small that they can only be seen with electron microscope.2. Viruses have charcteristics of both living and non-living things.3. Structurally they are not like, cell and are only made up of proteins and nucleic acids.4. When they enter the body of any living organisms, they reproduce there like living organism.5. They look like non-living crystals when they are out of the body of a living organism.6. That is why they are placed between living and non-living things.7. All viruses are parasites and cause different diseases in their hosts.8. Viruses were discovered by Iwanowsky in 1892 from infected tobacco leaves. In 1935 W.M. Stanley isolated viruses in crystalline form from infected leaves of tobacco and observed them under electron microscope. Size of VirusViruses are of different sizes. Their size varies from 0.01um to 0.03um(um is micrometer = 1/10,00,000 meter) Shape of VirusViruses are of different shapes some are rounded, few are rod shaped, few polyhedral while some viruses look like tadpoles. Structure of VirusViruses have same biochemical nature. In spite of their different shapes, they are made up of only two parts, an outer "coat", and an inner "core". The core is made up of DNA or RNA (never both) and the coat is made of protein. The outer protein coat determines the shape of viruses. e.g. in bacteriophage (virus that lives in bacteria) protein coat consists of two parts, head and tail. DNA is present in the head region but the tail has only protein. Most of the animal viruses contain DNA whereas plant viruses have RNA core bacteriophage is also called phage virus. Viral Diseases in PlantsRing spot in different plants, yellow in sugar beet and mosaic disease in tobacco, potato, tomato, bean and cabbage are the various diseases of plants, caused by viruses.

Viral Diseases in AnimalsMouth and foot disease in cattle and cowpox in horses, buffalo and cows are caused by viruses. Viral Diseases in HumansIn human beings, viruses produce common cold, influenza, small pox, yellow fever, polio, infectious hepatitis, cancer and AIDS. Ways of Viral Transmission1. Through droplets produced during coughing and sneezing.2. Through contact.3. By air, contaminated water and food.4. Through insects.5. By reuse of already used syringes.6. By un-sterilized surgery equipments. BacteriaBacteria are found every where in air, water, living and dead bodies of organisms and even in glaciers and hot springs. These are unicellular micro-organisms. Discovery of BacteriaLeeuwenhoek discovered bacteria in 1697 for the first time. Later, Louis Pasteur and Robert Koch worked on them. They discovered that bacteria produce many diseases in men and animals.

Size of BacteriaBacteria (singular : bacterium) range from 1um to 10um in length and from 0.2um to 1um in width and can be observed under light microscope. Types of BacteriaOn the basis of shape and form, bacteria are of four types. These are as follows:1. Rounded - Cocci (singular; coccus)2. Rod-like - Bacilli (singular; bacillus)3. Spiral shaped - Spirilla (singular; spirillum)4. Comma like - Vibrios (singular; vibrio)Bacteria occur both singly and in colonies. Cocci bacteria are found in groups of two or four, or in irregular groups and even in the form of long beads. Baccilli are found singly or may join end to end to form long threads. But Spirilla and Vibrios occur singly. Structure of Bacteria1. Bacteria are single celled prokaryotic organisms.2. Bacterial cell is surrounded by a cell wall which is made of carbohydrates and amino acids.3. Some bacteria have an additional slime capsule around their cell wall, which protects them and prevents them from drying.4. Ribosomes help in synthesis of proteins. Nucleus is absent in bacterium. However, only a single large circular molecule of DNA is present which is surrounded by a clear zone of cytoplasm. It is known as nucleoid. This is not bounded by a nuclear membrane.5. In addition to main bacterial DNA small, circular molecules of DNA called plasmids are also found. Plasmids play an important role in transmission of some heredity characteristics. Plasmids are also used a vectors in genetic engineering.6. Motile (which can move) bacteria like bacilli are spirilla have one or more thread like flagella (singular; flagellum) which help them in their locomotion. Non motile bacteria like cocci lack flagella. Economic Importance of Bacteria

It is generally thought that bacteria are fatal and harmful organisms and there is no beneficial aspect. But this is wrong impression. There are number of bacteria which are not only beneficial for mankind but are also essential for living system. Bacteria play very important role in the life of living organisms. Beneficial Bacteria Ecological ImportanceThese, along with fungi, help to decompose dead organisms and their refuse into simpler substances replenishing the raw materials in the soil and atmosphere and can thus purify the environment. Bacteria and Nitrogenous Compounds in SoilThese bacteria are called nitrogen fixing bacteria. Another kind of bacteria live in the soil, called nitrifying bacteria which convert ammonia into nitrite and then to nitrate, enhancing the amount of nitrogen in the soil. In this way fertility of soil is increased. Industrial and Commercial Purposes1. These are used in manufacturing butter, cheese and yogurt.2. These are used in processing of commercial fibers, leather, coffee, tobacco and vinegar.

Bacteria Synthesize EnzymesBacteria synthesize cellulose enzyme in the stomach of herbivore animals which helps in the digestion of food. Some bacteria also synthesize vitamin "B" and "K" in the large intestine of man and other mammals. Bacteria as Bio-InsecticidesRecently the use of bacteria in bio-insecticides has become popular. Harmful Bacteria1. Bacterial decomposition on one hand is beneficial but on other hand causes damage to food, wood, clothes and other things.2. Denitrifying bacteria in soil decrease the amount of nitrogen in soil and reduce the soil fertility. These are called identifying bacteria.3. Many bacteria are harmful and cause many diseases in plants, such as canker disease in citrus fruits, rot and fire blight in peach, pear and apple, and potato scab in potato.4. In animal like cattle bacteria cause T.B and anthrax. Bacteria also cause many diseases in man like T.B, Whooping Cough, Diphtheria, Typhoid, Pneumonia, Tetanus, Plague, Bacterial Dysentery, Cholera, Leprosy etc. Ways of Bacteria Transmission1. Whooping cough, Diphtheria, T.B and Pneumonia causing bacteria are transmitted from one person to other person through sneezes and cough droplets released in air.2. Bacteria causing Typhoid and Cholera, are transmitted from one organism to another through contaminated water and food.3. Plague and bacterial dysentery read through vectors like flies and animals. Cyanobacteria1. Cyanobacteria are also called blue green algae. They are simplest living organisms which have the ability to manufacture their own food by photosynthesis.2. Structurally they resemble bacteria. Bacteria and Cyanobacteria are prokaryotes and they are placed in kingdom Monera.3. Generally Cyanobacteria are found in moist places like of trees, rocks and soil, fresh water and oceans.

4. Some of them are symbionts and some are epiphytes.5. Cyanobacteria are usually unicellular and solitary. NOSTOCA common example of cyanobacteria which has filamentous structure which is found in the form a ball is called Nostoc. Characteristics of NostocThe important characteristics of Nostoc are:1. It has a filamentous structure which form a ball like structure of Nostoc.2. It floats on water.3. Each filament of Nostoc is unbranched and has a single row of rounded or oval cells.4. Each cell of Nostoc has double layered wall.5. The protoplasm is differentiated into two parts.6. Endoplasmic reticulum, mitochondria, golgi bodies and vacuoles are not present in the structure of Nostoc.7. Heterocyst are found which help in nitrogen fixation.8. Nostoc is an autotroph like other Blue-green-Algae. Taxonomic Position of NostocAccording to new classification, Nostoc belongs to kingdom prokaryota or Monera. Structure of NostocThe structure of Nostoc is filamentous. The filaments are interring mixed in agelatinuous mass forming a ball like structure. It floats on water. A single filament looks like a chain of beads. Each filament is unbranched and has a row of rounded or oval cellsSTRUCTURAL ORGANIZATION OF LIFE.

The Discovery of Cell and Cell Theory.

Discovery of CellIn 1665, an English biologist Robert Hooke invented first compound microscope and observed the sections of corks and leaves under this microscope. He noticed in them small box like chambers of same size which he called "cells". After this, biologists observed different organisms under the microscope. They found that structure of cells was complex. Cell TheoryIn 19th century, the compound microscope was highly advanced and biologists observed things just a micrometer apart. After this, a series of discoveries started, which provided basic information for cell theory.1. In 1831 - 33, Robert Brown discovered nucleus in cells of plants.2. In 1838, a German botanist Mathias Scheiden observed that all plants were made up of cells.3. In 1839, Theoclor Schwann obsrved that the bodies of of animals were made up of cells which were similar to plant cells.4. Thus, Schleiden and Schwann formulated the "Cell Theory". According to this, all organisms are made up of cells.5. In 1840, J. Purkinji gave the name "Protoplasm" to the things found inside the cells. At that time, cell was considered as a bag of thick dense substance containing a nucleus.Later on, resolving power and quality of microscopes were highly improved. Section cutting of tissues and cells and their staining became easier and better. It revealed that cell was not a simple mass of granular substance; instead it contained many sub cellular bodies called "Organelles". Each organelle has a definite job in the cell.

6. Human is made up of about 60 trillion cells. From Amoeba and unicellular algae to whales and tallest red wood trees, all' are made up of similar basic units called cell.s All animals and plants are thus made up of cells and cell products. Salient Features of Cell Theory1. All animals and plants are made up of cells and cell products. Among these some organisms are unicellular and some are multicellular.2. Cell is structural and functional unit of living organisms.3. New cells come from the divisions of pre-existing cell.

Electron Microscope

This is the most advanced form of microscope. Its resolving power is 250 times or more that of a compound microscope. In this microscope, a beam of electrons under high voltage is passed through the object and its image is reflected on to a screen through an electro magnetic lens to make a photograph.(Diagram)With the help of microscope, any object an be magnified up to 250,000 its original size. Comparison of Light Microscope and Electron Microscope

Light Microscope(i) The radiation source is light so it is called light microscope. (ii) Wavelength of light is 400 - 700 nm. (iii) Maximum resolution is 200 nm. (iv) Maximum useful magnification is X 1500 with eye. (v) Lenses are used. Electron Microscope(i) The radiation source is beam of electrons, so it is called Electron Microscope. (ii) Wavelength of beam of electrons is 0.005 nm. (iii) Maximum resolution is 0.5 nm. (iv) Maximum useful magnification is X. 250,000 on screen as image or photograph. (v) Electromagnets are used.

Structure of Cell There are two types of cells:1. Prokaryotic cell2. Eukaryotic CellProkaryotic cell lacks a membrane bound nucleus and membraned organelles e.g. bacterial cell while eukaryotic cell has a membrane bound nucleus and membraned organelles e.g. cells of plants and animals.With the help of light microscope and electron microscope, a typical Eukaryotic cell shows the following structural details.(Diagram)1. Cell Wall2. Cell Membrane3. Nucleus4. Cytoplasm

Cell WallIt is the outer most boundary of plant cells. It is rigid and non-living. It is chemically composed of Cellulose. The cell wall of fungi is made up of Chitin. The walls of some cells are thick and walls of some cells are thin. For example, in plants, xylem vessel elements and tracheids (which transport water and minerals) have thick walls whereas as parenchyma cells (which store water and food) have thin walls. The primary layer of cell wall is known as primary walls which are further strengthened by an additional layer called secondary wall especially in xylem vessels. Secondary wall is thicker than the primary wall. Electron microscope studies reveal that cellulose fibers in primary and secondary walls have a criss cross arrangement.FunctionsCell wall provides a definite shape, rigidity, protection and support to plant cell. Cell MembraneIt is a thin membrane which is also called Plasma membrane. It is present in cells of all plants and animals. It is outer most boundary of animal cell while in plant cells; it is present inner to cell wall. Both nucleus and cytoplasm are surrounded by cell membrane. According to fluid mosaic model, cell membrane is composed of two layers of lipids in which protein molecules are partially or completely embedded.FunctionsCell membrane is selectively permeable membrane. It means that it allows some things to pass through easily while some not. Thus, it controls the movement of material inside or outside the cell. NucleusIt is most important and distinct part of the cell. It is present in center of the animal cell while in plant cell it is pushed on one side due to large central vacuole. It is also surrounded by a membrane which is called membrane. Under microscope, it to be doubled and nuclear electron appears porous.1. The number of chromosomes is fixed for each species. This number is called diploid number (2n). E.g human's cell has 46 chromosomes, cell of Radish has 18 chromosomes, and cell of union has 16 chromosomes.2. Chromosomes are composed of protein and DNA.3. In the nucleolus (plural, Nucleoli) ribosomal RNA is formed which helps in the formation of ribosome. CytoplasmIt is viscous opaque substance. It is present between nuclear membrane and cell membrane. In a living cell, many types of organelle of different sizes and shapes are found. It contains many insoluble granules of storage substances. There are also present organic compounds like carbohydrates, proteins, lipids (fats), enzymes and inorganic compounds like water and salts.FunctionsCytoplasm provides chemicals, site and environment for different biochemical reactions.

Organelles in Cytoplasm

MitochondriaThey re oval or rod like in shape. Their membrane is doubled. Outer membrane is smooth while inner membrane has enfolding in the mitochondrial matrix. These enfolding are called cristae. The cristae bear small rounded bodies which are called particles.

There are about one million elementary particles in one mitochondrian. They are involved in oxidative phosphorylation. They also have many respiratory enzymes. Number of MitochondriaTheir number is different in different cells of different animals. In more active cells, their number is more than 1000 e.g. liver cell.s The cells of ear lobes have a few number of mitochondria.FunctionMitochondria re very important organelles of Eukaryotic cell.s Many oxidation-reduction reaction occur in the mitochondria. As a result energy is produced. This energy is used by cell in various functions. This the reason that mitochondria are also called "Power house of cell". Golgi BodiesThey were discovered by Camillo Golgi. They consist of set of smooth, flattened sacs which are called cristernae. The cristemae are stacked over each other. Golgi bodies are in the form of network in some cells or meshwork or filamentous in other cells.FunctionGolgi bodies store the secretions, convert them into finished products and pack them at their margins into small rounded sacs called Golgi vesicles, which transport secretions outside the cell. Endoplasmic ReticulumIt is a network of tubules and cristemae extending throughout the cytoplasm from nuclear membrane to cell membrane.Types of Endoplasmic ReticulumFollowing are the two types of Endoplasmic Reticulum: Smooth Endoplasmic ReticulumIt is also called non-granular endoplasmic reticulum because ribosomes are not attached on it. Rough Endoplasmic ReticulumIt is also called granular endoplasmic reticulum because ribosomes are attached on it.Functions1. Smooth endoplasmic Reticulum plays a role in synthesis of lipids.2. Rough endoplasmic reticulum plays an important role in synthesis of proteins. It also transports materials from one part of cell to other.3. Endoplasmic reticulum provides support to the cell. RibosomesThese are tiny granular structures. These re not bounded by any membrane. These are formed in the nucleolus nd re freely dispersed in cytoplasm or attached with endoplasmic reticulum.FunctionsRibosome is involved in protein synthesis. It is the only organelle which is also found in Prokaryotic cell. PlastidsThese are pigment containing organelles. These are found in plant cells. Many plastids have one or more than one pigments.Types of PlastidsPlastids are of three types which are as follows: ChloroplastsThese are mot important plastids. These re green in colour and found in green parts of plant. These contain chlorophyll which helps in photosynthesis. The study of ultra structure reveals that

it is bounded by a double membrane.Inside the chloroplast there is present a semifluid matrix called called stroma, which is made up of proteins and other chemicals. The inner membrane forms stacked membrane system which becomes suspended in the stroma. Each membrane stack is called granum (plural grana. The membranes of grana are the sites where photosynthesis occurs in the presence of sun light.FunctionsIn chloroplasts, photosynthesis takes place and food is prepared for plant. ChromoplastsThese are second type of plastids. These are of various colours other than green. In plants, colours other than green are due to chromoplasts. These are present in the petals of the flowers and in the ripened fruit.FunctionsThese help the plants in pollination. These impart various colours to petals and fruits. LeucoplastsThese are third type of plastids. These are colourless plastids. These are triangular tubular or of any other shape. These are found in food storage prts of the plant especially the roots and tubers. CentrioleIn animal cells, two centrioles are present near the nucleus. There are hollow and cylindrical. Each centriole consists of nine triplets of microtubules.FunctionCentrioles help in spindle formation during division of animal cell. Spindle is composed of protein fibers which help the chromosomes to move. Centrioles are absent in cells of higher plants. In some cells, centrioles help in the formation of flagella or cillia. VacuoleIt is a fluid filled small sac which is bounded by a single membrane. In animal cells, these are comparatively smaller in size but many in number while in plant cells; there is a large central vacuole which is filled with water and salts.FunctionsIn small organisms, extra water and wastes are excreted through contractile vacuoles, while food is digested in food vacuole. Increase in size of vacuole results in an increase in size of cell.

Difference between Prokaryotic Cell and Eukaryotic CellProkaryotic Cell(i) The organisms made of prokaryotic cells are called prokaryotes e.g. bacteria and cyanobacteria. (ii) These cells lack a membrane bound nucleus. The hereditary material (DNA) is found in cytoplasm. (iii) These cells lack membrane bound organelles. (iv) Ribosomes are of small size in and freely scattered cytoplasm. (v) Cellulose is absent in cell wall, rather it is made up of peptido-glycan or murein. (vi) These cells are simple and of smaller size (average diameter 0.5 - 10 nm) Eukaryotic Cell(i) The organisms mae of Eukaryotic cells are called Eukaryotes, e.g. animals, plants fungi and protists. (ii) These cells have a membrane bound nucleus; and hereditary material is found inside the nucleus.

(iii) These cells have membrane bound organelles. (iv) Ribosomes are of large size and are present in endoplasmic reticulum free in cytoplasm. (v) Cellulose is present in cell wall of plant cells. The cell wall of most of fungi is composed of chitin. (vi) These cells are complex and of larger size (Average diameter 10-100nm)

MitosisIt is that cell division in which the number of chromosomes in both daughter nuclei remains same as in parent nucleus.(Diagram)Events of MitosisMitosis has the following phases:1. Prophase2. Metaphase3. Anaphase4. Telephase5. Cytokinesis Prophase1. In this phase, coiling of chromosomes starts and their length decreases but diameter increases. It means that chromosomes become shorter and thicker, this process is called condensation.2. Microtubules arrange to form a structure called spindle.3. In animal cell, there are also present centrioles on both poles of spindle. From each centriole, small microtubules or fiber arise forming a star shaped aster.4. Spindle fibers, centrioles and aster collectively form mitotic apparatus. In plants, this apparatus is made up of only spindle fibers as asters are absent in these cells. 5. Nuclear membrane is broken down. Nucleolus disappears and chromosomes scatter over the spindle fiber.6. Each chromosome consists of two similar threads like structure called chromatids, these chromatids are united to each other by means of centromere. Metaphase1. The chromosomes arrange themselves on equator of the spindle to form an equatorial plate. In this condition, chromosomes become more visible.2. The chromosomes are attached at their centromere to one spindle fiber from each pole. Anaphase1. First of all spindle fibers shrink and become short.2. The centromere of each chromosome then divides and the two chromatids of each chromosome start separating. At this stage these are not called chromatids because these are no in united condition these are called chromosomes.3. These chromosomes start moving slowly towards the opposite poles. In this way, one set of chromosomes moves towrds one pole while other towards the other pole. Telophase1. The chromosomes reach their poles.2. The chromosomes uncoil and become less visible.3. Nuclear membrane reforms and nucleolus appears too. Therefore two nuclei are formed. Each daughter nucleus has the same number of chromosomes as the parent cell. Cytokinesis

The division of cytoplasm is called cytokinesis. It begins at the last stages of nuclear division. In plant cell, cytoplasm divides by formation of cell plate which is also called phragmoplast. It gradually extends outward and finally two daughter cells are separated.In animals, cytoplasm divides by furrowing. During this, there occurs inward pinching of cell membrane resulting into two daughter cells. In mitosis, two daughter cells are formed from one parent cell which are identical to their parent cell. Significance of Mitosis1. Mitosis occurs in all types of somatic cells.2. Daughter cells formed as a result of mitosis have same number of chromosomes as that of parent cell. In this way, all cells of body of an organism have same number of chromosomes.3. Zygote divides by mitosis to form embryo and after hatching or birth, mitosis continues up to maturity of an individual.4. Mitosis also results in growth and repairing of damaged or worn out tissues.5. Healing of wounds is also due to mitosis.

MeiosisIt is that type of cell division in which cytoplasm and nucleus divides twice and as a result of this, four daughter cells are formed and chromosome number is reduced to half. It means that one diploid (2n) parent cell divides to form four haploid (n) daughter cells.Meiosis consists of two sub divisions:1. Meiosis I2. Meiosis II

Meiosis IIt has following stages:Prophase I1. It is lengthy than prophase of mitosis. It is very important phase. It is divided into five stages during which there is continuous condensation of chromosomes.2. The important process of this phase is synapsis in which homologous chromosomes pair with each other length wise.3. Each pair consists of four chromatids or two chromosomes.4. After synapsis, the process of crossing over takes place. In this, homologous chromosomes exchange their chromatids parts at certain places.5. At end of this phase, nuclear membrane breaks up. Nucleolus disappears and chromosomes scatter over the spindle.6. Like mitosis, mitotic apparatus is also formed here.(Diagram) Metaphase I1. The chromosomes arrange on scatter of the spindle.2. Here, homologous bivalents arrange at equatorial plate of spindle.3. Only one spindle fiber is attached to each chromosome. Anaphase I1. Homologous pairs of chromosomes are separated.2. Spindle fibers contract.3. Chromosomes begin to move towards the opposite poles.4. This phase is different from metaphase of mitosis because half the number of chromosomes

moves towards each pole and each chromosome still has two chromatids. Telephase I1. Half the number of chromosomes reach at opposite poles.2. Chromosomes again increase their length.3. Nucleolus reappears. Nuclear membrane is reformed and in this way two daughter nuclei are formed.4. Now cytoplasm divides and two daughter cells are formed. Each cell is haploid (n). Meiosis IIIt is similar to mitosis. The haploid cells formed in meiosis I pass through phases of meiosis II and ultimately four haploid (n) daughter cells are formed. These cells afterwards change into spores (in plants or gametes (animals) Significance of Meiosis1. Meiosis takes place only in germ mother cells which form gametes or spores.2. It maintains the chromosome number of a species constant generation after generation.3. If gametes had the same number of chromosomes as in somatic cells, the number of chromosomes would have doubled after each generation in a species.4. The number of chromosomes is constant for each species. During meiosis; gametes (both and) formed are haploid.5. Gametes unite to form a diploid zygote.6. During meiosis, pairing of chromosomes takes place which is called synapsis.7. Exchange of genetic material occurs during meiosis. In this way variations are produced which are raw material for evolution.

TissuesA group of cells which perform same function is known as tissue. The tissues are divided into different types on the basis of their form and structure or function. Plant TissuesFollowing are the types of tissues in plants:1. Simple Tissues2. Compound Tissues Simple TissuesSimple tissues consists of only one type of cells. In plants, they are of following types:1. Meristematic or embryonic tissues2. Permanent Tissues Meristematic Tissues1. Cells of this tissue have ability to divide.2. Cytoplasm is dense nd nucleus is big in these cells.3. Vacuoles are smaller if present other wise absent.4. All cells are identical.5. There are no intercellular spaces.6. Their walls are thin and nucleus is present in centre of cell.7. These tissues found on apex of root or shoot are called apical meristems. The cells of these tissues divide; and redivide to add primary tissue for elongation of setm or root.This type of growth is called primary growth. 8. Meristematic cells are also found on the lateral sides of roots and stems as lateral(cambium) or intercalary meristem, and these add, secondary tissues. In this way, thickness of stem or root is

increased. This type of growth is called secondary growth. Permanent TissuesThe cells of this tissue lack the ability to divide and they originate from meristems. These are given below:a. Epidermal Tissuesb. Ground Tissues (a) Epidermal Tissues1. They are found as the outermost covering of leaf, stem or root.2. There are non intercellular spaces.3. Cells are rectangular in shape.4. In the epidermal tissues of stem and leaves, there are small openings called stomata for gaseous exchange. (b) Ground Tissues1. Most of the portion of body of herbaceous plants consists of ground tissues i.e. parenchyma. 2. They are thin walled.3. Cells are large in size.4. Cells sometimes may develop the ability to divide.5. Their main functions are to prepare and store food and water. Supporting or Mechanical TissuesThese provide strength flexibility to the plant. They are of following two types:a. Collenchyma Tissuesb. Sclerenchyma Tissues (a) Collenchyma Tissues1. These consist of living cells.2. Their walls are not uniformly thickened.3. Usually walls are thickened at angles.4. These are more flexible or elastic than sclerenchyma.5. These tissues are found in stem, in midrib of leaves and in cortex of petiole. (b) Sclerenchyma Tissues1. These consist of dead cells.2. Their walls are highly thickened due to deposition of lignin.3. Lignin provides hardness and strength to the cell.4. These cells are without protoplasm.5. Sclerenchyma cells are of two types, •Stone cells having uniformly thick cell walls; found in testa of seeds. •Fibrous cells which are elongated cells found in xylem and phloem for strength and transport of water Compound TissuesThese are the tissues which consists of two or more than two types of cells. But all cells perform a common function.These Tissues are of following types: Xylem Tissue1. This vascular tissue transports water in the plants and provides strength to the plant.2. In this tissue, there are present xylem parenchyma and two types of thick walled dead cells.• Long cells which are called vessel elements or cells. They are joined together to form long pipe-lines. These transport water from roots to leaves.

• Spindle shaped cells, which are called tracheicts. These provide strength to root and shoot etc. 3. Xylem conducts water in one direction that is from roots towards the stem and leaves. Phloem Tissues1. This vascular tissue transports food in the plants.2. It helps in two directional conduction of food material i.e. from leaves to roots and vice-versa.3. This tissue mostly consists of living cells. There are three types of cells (a) Phloem Parenchyma(b) Sieve Tube Cells(c) Companion Cells (a) Phloem ParenchymaThese cells store surplus water and food. They can start to divide when needed. (b) Sieve Tube CellsTheir end walls have small pores called sieve plates. These cells join to form long pipelines, which are called sieve tubes. There is no nucleus in these cells. Their main function is to transport food. (c) Companion CellsIn some plants, each sieve tube cell is accompanied by a companion cell. The companion cell has a nucleus. The corn cell controls the movement of food through sieve tubes. Animal TissuesFollowing are four types of tissues that are found in animals:1. Epithelial Tissues2. Connective Tissues3. Muscle Tissues4. Nerve Tissues Physics....Chapter 7

CIRCULAR MOTION AND GRAVITION.

Centripetal Force Definition"The force that causes an object to move along a curve (or a curved path) is called centripetal force."

Mathematical ExpressionWe know that the magnitude of centripetal acceleration of a body in a uniform circular motions is directly proportional to the square of velocity and inversely proportional to the radius of the path Therefore,a(c) < v2 (Here < represents the sign of proportionality do not write this in your examination and 2 represents square of v)a(c) < 1/rCombining both the equations:a(c) < v2/r From Newton's Second Law of Motion:F = ma=> F(c) = mv2/rWhere,• Fc = Centripetal Force

• m = Mass of object • v = Velocity of object • r = Radius of the curved path Factors on which Fc Depends:Fc depends upon the following factors:• Increase in the mass increases Fc. • It increases with the square of velocity. • It decreases with the increase in radius of the curved path.Examples• The centripetal force required by natural planets to move constantly round a circle is provided by the gravitational force of the sun. • If a stone tied to a string is whirled in a circle, the required centripetal force is supplied to it by our hand. As a reaction the stone exerts an equal force which is felt by our hand. • The pilot while turning his aeroplane tilts one wing in the upward direction so that the air pressure may provide the required suitable Fc. Centrifugal ForceDefinition"A force supposed to act radially outward on a body moving in a curve is known as centrifugal force."ExplanationCentrifugal force is actually a reaction to the centripetal force. It is a well-known fact that Fc is directed towards the centre of the circle, so the centrifugal force, which is a force of reaction, is directed away from the centre of the circle or the curved path.According to Newton's third law of motion action and reaction do not act on the same body, so the centrifugal force does not act on the body moving round a circle, but it acts on the body that provides Fc.Examples• If a stone is tied to one end of a string and it is moved round a circle, then the force exerted on the string on outward direction is called centrifugal force. • The aeroplane moving in a circle exerts force in a direction opposite to the pressure of air. • When a train rounds a curve, the centrifugal force is also exerted on the track. Law of Gravitation IntroductionNewton proposed the theory that all objects in the universe attract each other with a force known as gravitation. the gravitational attraction exists between all bodies. Hence, two stones are not only attracted towards the earth, but also towards each other.StatementEvery body in the universe attracts every other body with a force, which is directly proportional to the product of masses and inversely proportional to the square of the distance between their centres. Mathematical ExpressionTwo objects having mass m1 and m2 are placed at a distance r. According to Newton's Law of Universal Gravitation. F < m1m2 ((Here < represents the sign of proportionality do not write this in your examination) Also F < 1/r2 (Here 2 represents square of r) Combining both the equations :

F < m1m2/r2 Removing the sign of proportionality and introducing a constant: F = G (m1m2/r2) Physics....Chapter 6

STATICS.

DEFINITIONS 1. StaticStatics deals with the bodies at rest under number of forces, the equilibrium and the conditions of equilibrium.

2. Resultant ForceThe net effect of two or more forces is a single force, that is called the resultant force. 3. Moment Arm The perpendicular distance between the axis of rotation and the line of the action of force is called the moment arm of the force. TORQUEIt is the turning effects of a force about an axis of rotation is called moment of force or torque. FACTORS ON WHICH TORQUE DEPENDS1. The magnitude of the applied force.2. The perpendicular distance between axis of rotation and point of application of force.

REPRESENTATIONTorque may be represented as,Torque = Force * moment armT = F * d CENTRE OF GRAVITYThe centre of gravity is a point at which the whole weight of the body appears to act.

Centre of Gravity of Regular Shaped Objects We can find the centre of gravity of any regular shaped body having the following shapes:1. Triangle: The point of intersection of all the medians.2. Circle: Centre of gravity of circle is also the centre of gravity.3. Square: Point of intersection of the diagnonals.4. Parallelogram: Point of intersection of the diagonals.5. Sphere: Centre of the sphere.

Centre of Gravity of Irregular Shaped Objects We can find the center of gravity of any irregular shaped object by using following method. Drill a few small holes near the edge of the irregular plate. Using the hole A, suspend the plate from a nail fixed horizontally in a wall. The plate will come to rest after a few moments. It will be in a position so that its centre of gravity is vertically below the point of suspension.Now, suspend a plumb line from the supporting nail. Draw a line AA' in the plate along the plumb line. The centre of gravity is located somewhere on this line.Repeat the same process using the second hole B. This gives the line BB' on the plate. Also

repeat this process and use hole C and get line CC'.The lines AA', BB' and CC' intersect each other at a point. It is our required point, i.e.e the centre of gravity. We can use this procedure with any irregular shaped body and find out its centre of gravity. EQUILIBRIUMA body will be in equilibrium if the forces acting on it must be cancel the effect of each other.In the other word we can also write that:A body is said to be in equilibrium condition if there is no unbalance or net force acting on it. Static EquilibriumWhen a body is at rest and all forces applied on the body cancel each other then it is said to be in static equilibrium. Dynamic EquilibriumWhen a body is moving with uniform velocity and forces applied on the body cancel each other then it is said to be in the dynamic equilibrium. CONDITIONS OF EQUILIBRIUMFIRST CONDITION OF EQUILIBRIUM"A body will be in first condition of equilibrium if sum of all forces along X-axis and sum of all forces along Y-axis are are equal to zero, then the body is said to be in first condition of equilibrium."( Fx = 0 Fy = 0 ) SECOND CONDITIONS OF EQUILIBRIUM"A body will be in second condition of equilibrium if sum of clockwise(Moment) torque must be equal to the sum of anticlockwise torque(Moment), then the body is said to be in second condition of equilibrium." Sum of torque = 0 STATES OF EQUILIBRIUMThere are following three states of Equilibrium:1. First State (Stable Equilibrium)A body at rest is in stable equilibrium if on being displaced, it has the tendency to come back to its initial position.When the centre of gravity of a body i.e. below the point of suspension or support, then body is said to be in stable equilibrium. 2. Second State (Unstable Equilibrium)If a body on displacement topples over and occupies a new position then it is said to be in the state of unstable equilibrium.When the centre of gravity lies above the point of suspension or support, the body is said to be in the state of unstable equilibrium. 3. Third StateIf a body is placed in such state that if it is displaced then neither it topples over nor does it come back to its original position, then such state is called neutral equilibrium.When the centre of gravity of a body lies at the point of suspension, then the body is said to be in neutral equilibrium __________________Physics...Chapter 4

KINEMATICS.

DEFINITION "It is the branch of Physics which deals with description of motion without reference to any opposing or external force".

MOTION"When a body changes its position with respect to its surrounding so the body is said to be in the state of motion".TYPES OF MOTIONThere are three types of motion:1, Linear or Translatory motion2, Rotatory motion3, Vibratory motion

1. Linear or Translatory MotionIf a body moves in a straight path so the body is to be in Linear motion or Translatory motion.ExampleA bus is moving on the road, A person is running on the ground.

2. Rotatory MotionIf a body spins or rotates from the fixed point ,so the body is to be in Rotatory motion.ExampleThe blades of a moving fan, The wheel of a moving car.

3. Vibratory MotionTo and fro motion about the mean point so the body is to be in Vibratory motion.ExampleMotion of a spring.

REST"When a body does not change its position with respect to its surrounding so the body is said to be in the state of rest".ExampleA book is laying on the table,A person is standing on floor,A tree in the garden.

SPEED"The distance covered by a body in a unit time is called speed."OR"The rate of change of distance is called speed." FORMULA Speed = Distance/Timeor V = S/t UNITThe S.I unit of speed in M.K.S system is Meter/second.or m/s

Kinds Of Speed1. Uniform SpeedIf a body covers an equal distance in equal interval of time so the body is said to be in uniform speed.

2. Variable speedIf a body does not cover an equal distance in equal inteval of time so the body is said to be in variable speed. VELOCITY"The distance covered by a body in a unit time in a particular direction is called velocity."OR"The rate of change of displacement is called speed."OR"Speed in a definite direction is called velocity." FORMULAVelocity = Displacment/Timeor V = S/t

UNITThe S.I unit of Velocity in M.K.S system is Meter/second.or m/s Kinds Of Velocity1. Uniform VelocityIf a body covers an equal distance in equal interval of time in a Constant direction so the body is said to be in uniform Velocity. 2. Variable VelocityIf a body does not cover an equal distance in equal interval of time in a particular direction so the body is said to be in variable velocity. ACCELERATION"The rate of change of velocity is called acceleration."OR"Acceleration depends upon the velocity if the velocity continously increases or decreases the accelerattion will be produced." 1. Positive AccelerationIf the velocity continously increases then the acceleration will be positive.2. Negative accelerationIf the velocity continously decreases then the acceleration will be negative. FORMULAAcceleration = change of velocity/Timeor a = (Vf-Vi)/tPhysics...Chapter 3

SCALAR AND VECTORS

SCALAR"Scalar quantity are those physical quantity which are completely specified by their magnitude

express with suitable unit. They do not require any mention of the direction for complete their specificaton is called scalar quantity."OR

" Scalar quantity are those physical quantity which require magnitude , express with suitable unit only is called scalar quantity."

CHARACTERISTICS OF SCALAR QUANTITY1, Scalar quantity can be added,subtracted,multiplied,divided according to the ordinary algebraic rule.2, Two scalars are equal if they have same unit.

REPRESENTATIONIt can be represented by the numbers with decimals. (positive negative)EXAMPLEMass,Distance,Temperature,volume,speed e.t.c

VECTOR"VECTOR quantity are those physical quantity which do not require only their magnitude express with suitable unit. But they also require a particular direction for complete their specificaton is called vector quantity."OR" vector quantity are those physical quantity which require magnitude , express with suitable unit as well as proper direction is called vector quantity."

CHARACTERISTICS OF VECTOR QUANTITY1, vector quantity can not be added,subtracted,multiplied, divided according to the ordinary algebraic rule.2, It can be added,subtracted,multiplied,divided according to the some speciall rules like head and tail rule,Graphical method e.t.c.3, vector always treats as positive. REPRESENTATIONIt can be represented by an arrow with headline. The length of an arrow represents its magnitude and the headline represents the direction of the vector(figure 1.1) ------------------------------------->(figure 1.1)EXAMPLEWeight,Displacement,Velocity,Acceleraton,Torque,Mo mentum e.t.c ADDITION OF A VECTOR"The process of combining of two or more vector to produce a signal vector having the combinig effect of all the vector is called the resultant of the vector and this process is known as the addition of a vector". HEAD AND TAIL RULESuppose we have two vector A and B having the different magnitude and direction.1, First of all chose a suitable scale and representation of all the vector have been drawn on the paper.2, Put all the vector for finding the resultant of given vector such that the head of the first vector

join the tail of the second vector.3, Now join the tail of the first vector with tail of the second vector such that it join the two vector with head to head and tail to tail by another.4, The new vector R will be the resultant of the given vector.5, It can be measured by the Dee or any suitable mean.This method is called the head and tail or tip to tail rule. / \ / \/ | / |/ | / | R / | B / | / |/ |/ | /-------------->ARESOLUTION OF A VECTOR"The process of splitting up of a signal vector into two or more vector is called the resolution of a vector"OR"The process of splitting up of a signal vector into its components is called the resolution of a vector" RECTANGULAR COMPONENTSA vector which is not along x-axis or y-axis it can be resolved into infinite number, but generally a vector can be resolved into its components at a right angle to each other MATHEMATICALLY PROVED suppose a vector F is denoted by a line AB which makes an angle @ with horizontal surface OX. From a point A draw perpendicular to the horizontal surface OX.A/ \ / \ / | / |/ | / | F / | B Fy/ | / |/ |/ @ | B O /----------------> XFx

The line AB represents its vertical component and it is denoted by Fy.The line OB represents its horizontal component and it is denoted by Fx. Now in the triangle AOB

Sin@= AB/OA {sin@= Perpendicular/Hypotonuse} or sin@= Fy/F or Fy= Fsin@ Similarly Cos@= OB/OA {sin@= Base/Hypotonus} or Cos@= Fx/F or Fx= FCos@ For the triangle Tan@= AB/OB {Tan@= per/hyp) or Tan@= Fy/Fx or @=Tan-1 =Fy/Fx SUBTRACTION OF A VECTOR"It is defined as the Addition of A to the negative of a B is called the subtraction of a vector (A-B)" Physics...Chapter 2

MEASUREMENTS.

Definitions 1. MeterThe length of the path traveled by light in vacuum in 1/299,792,458 of a second is known as meter.Length is a fundamental unit used for measurements of length, distance and height. It is equal to the distance between two marks on a Platinum-Iridium bar kept at 0 C in International Bureau of Weight and Measurements (IBWM) near Paris. 2. KilogramThe mass of a Platinum-Iridium cylinder kept at 0 C in International Bureau of Weight and Measurements (IBWM) near Paris is considered to be 1 kilogram.Kilogram is a fundamental unit used for measurements of mass. 3. SecondIt is equal to the duration of 9,192,631,770 periods of radiation of Cesium-133 in ground state.Fundamental UnitsThe international system of units is based on seven independent units known as Fundamental or Basic Units. These are given below:1. Meter (m): length, distance, height (l)2. Kilogram (kg): mass (m)3. Second (s): time (t)4. Ampere (A): electric current (I)5. Kelvin (K): temperature (T)6. Mole (mol): amount of substance (n)7. Candela (cd): luminous intensity (Iv) Derived UnitsThe units that require two or more basic measurements of same units or different fundamental units for its definition are called derived units. 1. Square meter (m2): area (A)2. Cubic meter (m3): volume (V)3. Hertz (Hz): frequency (v)

4. Kilograms per cubic meter (kg/m3): mass density (p)5. Meter per second m/s: speed velocity (V)6. Radians per second (rad/s): angular velocity (w)7. Meters per second square (m/s2): acceleration (a)8. Newton (N) (kg.m/s2): force (F)9. Pascal (Pa) (N/m2): pressure (P)10. Joule (J)(N.m): work (W), energy(E), quantity of heat (q)11. Watt (W) (J/s): power (P)12. Coulomb (C) (A.s): quantity of electric charge (Q)13. Volt (V) (W/A): potential difference (V), electromotive force (E)14. Ohm (Omega): electric resistance (R)15. Farad (F)(A.s/V): capacitance (C)16. Weber (Wb)(V.s): magnetic flux (@)17. Henry (H) (V.s/A): inductance (E)18. Volts per meter (V/m): electric field strength (E)19. Newton per coulomb (N/C): electric field strength (E)20. Tesla (T) (Wb/m2): magnetic flux density (B)21. Ampere per meter (A/m): magnetic field strength (H)22. Joules per kilogram Kelvin: (J/kg.K) specific heat (Q) Vernier CallipersA vernier calipers is an instrument that is used to measure the length, diameter and depth of solid substances accurately up to 0.1mm. A vernier calipers has two scales, the main scale (MS) and vernier scale (VS). The vernier scale (VS) slides over the main scale (MS). Vernier Count (VC)The smallest measurement that can be made with the help of a vernier calipers is known as least count of vernier calipers or vernier count (VC). Least count of the vernier calipers is calculated byL.C = Value of Smallest Division of MS/Total Number of Divisions on VS Micrometer Screw Gauge A screw gauge is an instrument that is used to measure thickness of a wire, glass, plastic and metal sheets accurately up to 0.01mm. A micrometer screw gauge has two scales, the main scale (MS) and the circular scale (CS). The circular scale rotates over the main scale.

Least Count (LC)The smallest measurement that can be made with the help of a screw gauge is known as least count of screw gauge. Least count of the screw gauge is calculated by:L.C = Pitch of the Screw / Total number of divisions of CSwhere pitch is the distance between two consecutive threads of the linear screw. Physical BalanceA physical balance is an instrument that is used to find the mass of an object. Actually, it is the lever of the first kind with equal arms. Stop WatchA stop watch is an instrument that is used to measure accurately the time interval for any physical event. It can be used to measure the fraction of a second. Measuring Cylinder

A measuring cylinder is a glass cylinder of uniform area of cross section with a scale in cubic centimeter or millimeter marked on it. It is used to measure the volume of a liquid. Chemistry...Glossary

GLOSSARY

AcidityThe acidity of a base is defined as the number of ionizable hydroxyl groups in its molecule.

AnodeIt is an electrode through which electrons enter the external circuit. Alpha RaysThere are positively charged particles emitted from a radioactive substance. They carry two positive charges and are called helium nuclie. Analytical ChemistryIt is the branch of chemistry which discusses the analytical methods forgetting information about chemical compounds and chemical processes. Atomic NumberNumber of positively charged particles (protons) present in the nucleus of an atom. Atomic SizeAverage distance between the nucleus of an atom and its outermost electronic shell. Its units are nm or pm. Arrehenius AcidIt is a chemical compound which gives proton (H+) in water. Arrehenius BaseIt is a chemical compound which gives hydroxide ion (OH-) in water. Atomic SpectrumSpectrum of radiations emitted by the excited atoms when they come to the normal state. Acidic SaltsAn acidic salt is obtained when hydrogen atoms present in an acid, are partially replaced by metallic atoms. AlchemistA scientist trying to convert cheaper metals into precious metals is called Alchemist and this branch of chemistry is called Alchemy. Atomic MassThe mass of an element relative to the unit mass, which is 1/12th o the mass of C-12. AmpereThe amount of electric current which liberate one electrochemical equivalent of a substance per second during electrolysis of that substance is called ampere. BiochemistryIt is the study of chemical compounds present in living things. Balancing of Chemical EquationsEquating the atoms of reactants with those of products. Beta RaysThese are electrons emitted from a radioactive substance. Brownian Movement

The free movement of the molecules of gases and liquids is called Brownian movement. Bronsted AcidA compound which can donate proton. Bronsted BaseA compound which can accept proton. BasicityThe basicity of an acid is defined as the number, of ionizable hydrogen atoms present in its molecule. Basic SaltsA basic salt is obtained when the hydroxyl groups present in a base are partially replaced by some other groups. Boiling PointA temperature at which a liquid changes into gaseous state. ChemistryThe branch of science, which deals with the composition of matter changes in matter and the laws or principles which govern these changes. Chemical EquationThe representation of a chemical change in terms of symbols and formulas. Covalent SolidA solid in which there exist a covalent bond between atoms. Covalent BondIt is the force of attraction that arises between two atoms due to mutual sharing of an electron pair. Co-Ordinate Covalent BondWhen the shared pair of electrons is provided by one of the bonded atoms, a coordinate covalent bond is formed. Cohesive ForcesThe forces of attraction present between the particles of solid, liquid and a gas. Cathode RaysRays emitted from cathode in the discharge tube. Colloidal SolutionA solution in which solute particles are bigger than those present in a true solution and which cannot be filtered. ConductorA substance which allows electric current to pass through it. CathodeIt is an electrode through which electrons leave the external circuit. Concentration of a SolutionThe amount of a solute which has been dissolved in a particular amount of a solvent. Concentrated SolutionA solution, which contains an excess amount of a solute as compared to that of a solvent. CellThe vessel containing reacting substances in which transfer of electrons takes place is called cell.

CoulombIt is unit of electric current. When one ampere electric current is passed for one second the

quantity of electric current is one coulomb. Discharge TubeA glass tube containing a gas at a very low pressure and provided with electrodes to study the passage of electricity through the gas. Dipole-Dipole ForcesThe forces of attraction which originate due to the difference in electro negativities of the bonded atoms in polar molecules. DiffusionThe movement of molecules from a higher concentration to a Lowr concentration is called Diffusion. Dilute SolutionA solution, which contains a small amount of a solute as compared to that of a solvent. Double SaltsWhen two typical salts are crystallized together a double salt is formed. The physical properties of the crystals of double salt are different from those of the component salts Chemistry...General Differences

DIFFERENCES.

Metals and Non MetalsMetals

1. Metals have luster shine surface.2. Metals reflect heat and light.3. Metals conduct heat and electricity4. Metals are ductile and can be drawn into wire.

Non-Metals1. Non-Metals have no luster.2. Non-Metals usually don't reflect heat and light.3. Non-Metals do not conduct heat and electricity.4. Non-Metals are non ductile and cannot be drawn into wire.5. Non-Metals are non-malleable and can not form sheets. Homogeneous and Heterogeneous MixtureHomogeneous Mixture1. Those mixtures, which have uniform composition throughout their mass are called homogeneous mixtures.2. Homogeneous mixture has only one phase through out its mass.3. Homogeneous mixture are also known as solution.4. Examples: Salt and water, Sugar and water. Heterogeneous Mixture1. Those mixtures, which do not have uniform composition through their mass are called Heterogeneous Mixture.2. Heterogeneous Mixture has more than one phase through out its mass.3. Heterogeneous Mixture are not solutions.4. Examples: Rocks, Soil, Food products.

Molecular and Empirical FormulaMolecular Formula1. Formula which shows the actual number of atoms of each element present in a molecule is called Molecular Formula.2. Molecular Formula shows the structure of compound.3. Two or more compounds cannot have same Molecular Formula.4. Molecular Formula = n x Empirical Formula.5. It represents covalent compounds only. Empirical Formula1. formula, which shows the relative ratio of atoms of each element present in a molecule, is called Empirical Formula.2. Empirical Formula can not show the structure of compound.3. Two or more compounds can have same Empirical Formula.4. Empirical Formula = Molecular Formula / n5. It represent an ionic compound as well as a covalent compound. Symbol and FormulaSymbol1. A symbol is an abbreviation for the chemical name of an element and represents only one atom of the element.2. It represents one atom of an element.3. Symbol is written for elements.4. Examples: Na, Br, Cl, F etc. Formula1. Representation of compound in terms of symbols is called formula. It represents one atom of an element.2. It represents atoms of same or different elements present in one molecule.3. It represents an ionic compounds as well as a covalent compound.4. Examples: H2O, NH3 etc. Gram and Gram MoleculeGram1. The atomic mass of an element expressed in grams is called gram atomic mass.2. It is associated with element only.3. It is the mass of one atomic mole.4. One gram atom of any substance contains 6.02 x 10(23) atoms. (23 is the power of 10). Gram Molecule1. Molecular mass of any element or compound expressed in grams is called gram molecule.2. It is associated with element and compound.3. It is the mass of one molecular mole.4. One gram molecule of any substance contains 6.02 x 10(23) atoms. (23 is the power of 10). Atom and MoleculeAtom1. It is the smallest particle of an element which can enter into a chemical reaction.2. It is represented by a symbol of the element.3. It shows the properties of the element.4. It retains its identity in a chemical reaction. Molecule

1. It is the smallest particle of a substance which can exist and show all the properties of the substance.2. It is represented by a molecular formula of the substance.3. It shows the properties of the substance.4. It does not retain its identity in a chemical reaction. Exothermic and Endothermic ReactionsExothermic Reaction1. Those chemical reactions in which heat energy is evolved are called exothermic reactions.2. In exothermic reactions the enthalpy of products is lower than the reactants. H is therefore negative for an exothermic reaction.3. During endothermic reaction, the system becomes colder and net potential energy of substance increases.4. The energy is absorbed during these reactions.5. The temperature of reaction therefore decreases. Endothermic Reactions1. Those chemical reactions in which heat energy is absorbed are called endothermic reactions.2. In endothermic reactions the enthalpy of reactants is lower than the products. H is therefore positive in endothermic reaction.3. During endothermic reaction, the system becomes colder and net potential energy of substance increases.4. The energy is absorbed during these reactions.5. The temperature of reaction therefore decreases. Physical and Chemical PropertiesPhysical Properties1. The physical properties of a substance are those characteristics which serve to distinguish it from other substance but do not deal with its ability to undergo chemical changes.2. These are related to the physical state of matter.3. Examples: Formation of ice from water, formation of a magnet from ice etc. Chemical Properties1. The chemical properties of a substance indicate the ability of a substance to undergo chemical changes.2. They are related to the chemical change of a substance.3. Examples: burning of paper, rusting of iron. Chemistry....Chapter 7

ELECTRO-CHEMISTRY.

Electro-ChemistryThe branch of chemistry which deals with the study of chemical energy to electrical energy or electrical energy to chemical energy is called electro-chemistry.

ConductorsThose substances through which electric current can pass are called conductors. For example all metals are conductors.

Non-Conductors

Those substances through which electric current cannot pass are called non-conductors. For example plastic, wood are non-conductors.

ElectrolysisThe process in which electricity passes through the aqueous or infused state of some substance. The substances itself decompose into its component. This process is called electrolysis.

ElectrolyteThe compound in molten state or in aqueous solution through which electricity can pass are called electrolyte.

Non-ElectrolyteThose compounds through which electricity cannot pass are called non-electrolyte.

Strong ElectrolyteThe substances which are highly soluble and completely ionized are called strong electrolyte. For example acids, bases and salts are strong electrolytes.

Weak ElectrolyteThe substances which are not highly soluble and remain in un-ionized form are called weak electrolyte. ElectroplatingA process in which metal is deposited on the surface of another metal by electrolysis is called electroplating. Objectives of ElectroplatingDecorationIt is done for decoration. Noble and precious metals like gold or silver are deposited on the inferior metals to enhance their beauty and look beautiful. ProtectionElectroplating is done to protect the metals from rusting as well as from attack of other substance like organic acids and acidic gases. RepairIt can be used to repair the broken machinery by electroplating with other metals. Usually the metals like copper, silver, chromium, nickel and gold are used for electroplating. Procedure of ElectroplatingThe metal which is to be electroplated is first cleaned with sand and then washed with caustic soda solution and finally with a lot of water.This metal is made cathode and the metal which is going to be deposited is made anode. The electrolyte is a salt of metal being deposited and electroplating is carried out in a tank made of cement, glass or wood. It is called an electrolytic tank. The electrolyte should have following properties:1. It must be very soluble in water.2. It must be good conductor.3. Cheap4. May not easily oxidized or reduced or hydrolyzed.(Diagram) Chemistry....Chapter 6

SOLUTION AND SUSPENSION

SolutionA homogeneous mixture of different chemical substances which has uniform chemical composition through out and shows uniform physical properties is called solution. For example dissolve a small amount of copper sulphate in water the water will become blue. If this blue liquid is filtered, it will pass through the filter paper without leaving any solid. The mixture thus prepared is called a solution.

Binary SolutionA solution which is formed by mixing two substances is called binary solution. For example solution of glucose and water. SoluteThe component of a binary solution which is in lesser amount is called solute. For example in copper sulphate solution, copper sulphate is solute. SolventThe component of a binary solution which is in greater amount is called solvent. For example in copper sulphate solution, water is solvent. Saturated solutionA solution in which maximum amount of a solute has been dissolved at a particular temperature and in which the dissolved form of solute is at equilibrium with its undissolved form is called saturated solution. Unsaturated SolutionSolution which can dissolve further amount of a solute at a [particular temperature is called an unsaturated solution. Supersaturated SolutionThe solution which contains even more amount of solute required to prepare saturated solution is called super saturated solution. The hot saturated solution of compound like sodium thiosulphate does not crystallize its solute if cooled slowly without disturbance. Such a solution is called supersaturated solution. Dilute SolutionA solution which contains small amount of a solute as compared to the solvent is called dilute solution. Concentrated SolutionA solution which contains excess amount of a solute as compared to that of a solvent is called a concentrated solution. Concentrated SolutionThe amount of solute present in given quantity of solvent is called concentration of solution. The concentration of a solution can be expressed in many ways depending upon the amount o solute and solvent present in it. Concentration of SolutionThe amount of solute present in given quantity of solvent is called concentration of solution. The concentration of a solution can be expressed in many ways depending upon the amount of solute and solvent present in it. Percentage by Mass

The percentage of solute by mass is the mass of solute present in hundred part of the solution. For example 5% hydrogen peroxide solution by mass means that 5g hydrogen peroxide are dissolved in 95g of water to give 100g of solution.Percentage of Mass = (Mass of Solute/Mass of Solution) x 100 Percentage by VolumeThe concentration unit expresses the volume of solute present in 100cm3 of solution. For example 15% solution of alcohol by volume will mean that 15cm3 alcohols are present in 100cm3 of solution. (Here 3 represents cube)Percentage by Volume = (Volume of Solute/Volume of Solution) x 100 Molar SolutionThe solution that contains one mole of solute in 1dm3 of solution is called a molar solution. The concentration of this solution is expressed as M. MolarityMolarity of a solution is the number of moles of solute present in 1dm3 of the solution. It is expressed as M.M = Number of Moles of Solute/Volume of Solution in dm3orM = (Mass of solute/Molecular Mass) x (1/ Volume of Solution in dm3) CrystallizationThe process in which crystal separates from saturated solution on cooling is called crystallization. It is a useful process because it can be used to purify the impure solid compounds. It can also be used to separate a mixture of solids. HydrationThe ions surrounded by solvent molecules in solution are called solvated ions. If water is a solvent these ions are called hydrated ions. SuspensionA suspension in such a mixture in which solute particles do not dissolved in solvent and if filtrated its particles do not pass through the pores of filter paper. Colloidal SolutionIn a colloidal solution the solute particles are slightly bigger than those present in a true solution but not big enough to seen with naked eye. Standard SolutionA solution whose molarity (strength) is known is called Standard Solution. True SolutionA True Solution is such a mixture in which solute particles are completely homogenized in the solvent for example solution of sodium chloride or copper sulphate in water. SolubilitySolubility o a solute in a particular solvent is defined as the amount of solute in grams, which can dissolve in 100g of the solvent at a particular temperature to give a saturated solution.orThe amount of a solute in gram moles, which can dissolve in one kilogram of the solvent at a particular temperature, to give a saturated solution. Factors Affecting the SolubilityEffect of SolventSimilar solvents dissolve similar solutes, i.e. if the chemical structure and the electrical properties such as dipole moment of solute and solvent are similar, the solubility will increase. If

there is dissimilarity in properties, then either the solute will not dissolve or there will be very little solubility. Effect of SoluteDifferent solutes have different solubility's in a particular solvent e.g. if the saturated solutions of table sugar and sodium chloride are prepared, it is found that the concentration of sodium chloride solution is 5.3 molar while that of sugar solution is 3.8 molar. In other words, the solubility of sodium chloride in water is far greater than that of sugar. This is due to the fact that the attraction of sodium (Na+ and chloride (Cl-) ions with water is greater than that of sugar molecules with water. Effect of TemperatureChange in temperature has different effects on the solubility of different compounds. Usually the solubility increase with the increase in temperature but it cannot be taken as a general rule. The solubility of compounds like lithium carbonate, calcium chromate decreases with the increase in temperature. The solubility of gases in water also decreases with the increase in temperature. On the other hand, there are a large number of compounds whose solubility in water increase with the increase in temperature e.g. sodium nitrate, silver nitrate, Potassium chloride etc. the solubility of sodium chloride in water does not increase appreciably with the increase in temperatureSTATES OF MATTER.

States of MatterMatter has three states:1. Gas2. Liquid3. solidThese are physical states of matter. The three states of one matter may have different physical properties while their chemical properties are same. Water exists in three physical states solid (ice), liquid and gas(steam) has same chemical properties.

Kinetic Theory of MatterThe Kinetic theory was presented to explain the properties of gases and is called kinetic theory of gases. But this theory was also able to explain the composition of liquid and solid state of matter. So its is called Kinetic Theory of Matter.According to Kinetic Theory of matter:1. All matter is composed of atoms, molecules or ions.2. These particles have kinetic energy due to which they are in the state of motion.3. In gaseous state, these particles move in a straight line. They collide with one another and with the walls of container. In liquids the rate of their movement is very small but in solids, there is to and fro motion only.4. Generally material particles can have three types of movements, i.e. translational, rotational and vibrational. SolidsThe state of matter which has definite shape and volume is called solid. Properties of Solids1. Definite Volume and ShapeThe cohesive forces in solid substances are so strong that they keep their particles arranged in

fixed positions. So due to restrict movements of particles, the solids have definite volume and shape. 2.Motion of ParticlesThe solid particles have vibrational motion only because these particles are held in fixed position by strong cohesive forces. 3. Effect of HeatThe physical state of solid substance can be changed by heating. On heating solid is converted to liquid and gaseous state. Heat increases the kinetic energy of the particles and they start vibrating at higher frequency. At a particular temperature the vibrational motions become fast that they overcome the cohesive forces and solid melts to liquid. 4. Melting PointThe temperature at which the solid is converted to liquid on heating is called melting point. At melting point, the particles of solid loose their means position and their arrangement. The solid collapses and turns to liquid. 5. SublimationThe conversion of some solids directly into gaseous state on heating is called sublimation. Iodine, ammonium chloride and naphthalene change directly into vapour state upon heating. LiquidThe state of matter having definite volume but indefinite shape is called liquid. Properties of Liquid1. VolumeLiquids have definite volume. In liquid particles are very close to one another and have cohesive forces among the particles. Due to the presence of cohesive forces, liquids have definite volume and keep their level as well. 2. ShapeLiquids do not have any specific shape. They adopt the shape of the container. The molecules of liquid are able to move. Due to this random motion the molecules of liquid do not have fixed position and as a result, a liquid does not have any specific shape. 3. EvaporationConversion of liquid into its vapours at any temperature is called evaporation. The molecules of liquid come to the surface of liquid and escape by overcoming cohesive forces. So liquid is converted to vapours at all temperature. 4. Boiling PointThe temperature of a liquid at which its vapour pressure becomes equal to the atmospheric pressure is called boiling point. GasThe state of matter which does not have definite shape and volume is called gaseous state. Properties of Gaseous State1. Indefinite Volume and ShapeIn gaseous state, the molecules have insignificant cohesive forces among themselves. They move very fast in all possible directions. As a result, a gas neither has fixed shape nor a fixed volume. 2. Kinetic Energy of the Particle of a GasGas particles have very high kinetic energy as compared to liquid and solid state. 3. PressureThe molecules of a gas are in the state of random motion. The molecules of gas not only collide with one another but also with the walls of the container in which they are enclosed. Due to their

collision, the velocity of the molecules changes every moment. The pressure exerted by gas is also due to the collision of its molecules with the walls of the container. 4. Elastic CollisionThe collision of gas molecules is elastic in nature which means that the total energy of the colliding molecules remains the same before and after the collision. 5. Kinetic EnergyThe kinetic energy of molecules of gas is very high as compared with solid and liquid. Diffusion.The movement of molecules from a higher concentration to a lower concentration is known as Diffusion.If the concentration of molecules at a particular place is higher, they start moving towards a place where their concentration is lower. When the concentration of molecules at both the places becomes equal the process of diffusion stops. Diffusion in GasesThe molecules of one gas can diffuse easily into the molecules of other gas. For example if an open bottle of a perfume is kept in a room, its smell will spread uniformly throughout the room. The liquid perfume present in the bottle volatilized slowly and its vapours diffuse through out the room. Graham's Law of DiffusionScottish Chemist, Thomas Graham (1833) discovered that lighter gs can diffuse through porous pot faster than the heavier one. This is called Graham's Law of Diffusion.Hydrogen being lighter gas will diffuse faster than oxygen or carbon dioxide. Diffusion in LiquidsLiquid molecules can also diffuse because they have free movement. Since the molecules of liquid move comparatively slowly than gas molecule, their rate of diffusion are also lesser than gases. Brownian MovementRobert Brown (1927) discovered this phenomenon:The free movement of the molecules of gases and liquid is called Brownian Movement."When a pollen grain is put in water. The movement of pollen grain in water is observed by microscope. It is observed that pollen grain is continuously moving in all directions. This free movement of pollen grain was due to the free movement of water molecules. The colliding water molecules will also force pollen grain to move as well. The students can observe Brownian movement with the help of simple experiment.ExperimentPut a drop of milk on a microscope slide and cover it with cover slip. Put it under microscope and observe it. You will see small particle of fat moving randomly in milk. The movement of fat particles is actually due to the movement of water molecules in milk. Chemistry....Chapter 4

PERIODICITY OF ELEMENTS AND PERIODIC TABLE.

DefinitionsPeriodic TableA table of elements obtained by arranging them in order of their increasing atomic number in which elements having similar properties are placed in the same group is called Periodic Table.

GroupThe vertical column of elements in the periodic table are called Groups. PeriodThe horizontal rows of elements in the periodic table are called Periods. PeriodicityThe repetition of physical and chemical properties of elements periodically is called Periodicity of Properties. Periodic LawPhysical and chemical properties of elements are periodic function of their atomic masses. MetalElements which are good conductors of heat and electricity are malleable and ductile and have a metallic luster are called Metals like Sodium, Potassium, Gold, Copper etc. Non-MetalsElements which are non or bad conductor of heat and electricity are neither malleable or ductile and have no metallic luster are called Non-Metals like Carbon, Nitrogen, Chlorine etc. MetalloidsMetalloids are semi metals have the properties which are intermediate between a metal and non-metal like Boron, Silicon, Germanium, Arsenic, Antimony etc. Law of TriadsA German Chemist, Dobereiner (1829), arranged chemically similar elements in groups of three on the basis of their atomic masses called Triads and it was found that atomic mass of the middle element was approximately equal to the average of atomic masses of other two elements. This is known as Law of Triads. Drawback or DefectAs very few elements could be arranged in such groups, this classification did not get wide acceptance. Law of OctavesAn English Chemist Newland (1864) stated that if the elements were arranged in the ascending order of their atomic masses, every eight element will have similar properties to the first. This is knows as Law of Octaves. Drawback or Defects1. Noble gases were not discovered at that time and no place was reserved for the undiscovered noble gases.2. In the same way no blank spaces for the undiscovered elements were present in his table. Mendeleyv's Period Table and Periodic LawRussian Chemist, Mendeleyv's (186) who wa working separately from Lother Mayer published a table of elements.According to Mendeleyv's when the element were arranged in order of their increasing atomic mases, the elements with similar properties were repeated after regular interval and were placed one above the other.A table obtained in this manner is called Periodic Table. Mendeleyv's stated this periodicity in the form of Periodic Law. Important Features of Mendeleyv's Periodic TableThe important features of Mendeleyv's Periodic table are: Periods and GroupsThe horizontal rows which run from left to right in Periodic Table are called Periods and they are twelve in number.

The vertical rows which run from top to bottom in periodic table are called groups and they are eight in number. Vacant SpacesMendeleyv's left many vacant spaces for the still unknown elements. For example, next to Calcium (40) should be Titanium (48) but it resembled silicon (28) instead of Aluminium (27). He left vacant space for element with atomic mass 44. Discovery of New ElementMendeleyv's discovered new elements and also guessed their atomic mass and properties. Atomic Mass CorrectionMendeleyv's corrected the atomic masses of certain elements on basis of their properties and provided proper place to them in the periodic table. Defects in Mendeleyv's Periodic TableThe Mendeleyv's Period Table has following defects: Irregular Position of Some ElementsAccording to Mendeleyv's Periodic Law Potassium (39) should be placed before Argon (40) but he placed Argon (40) before Potassium (39) which goes against his law. Position of IsotopesMendeleyv's periodic table gives no indication about the position of isotopes. Structure of AtomMendeleyv's Periodic table gives no idea about structure of atoms. Position of Lanthanides and ActinidesLanthanides and Actinides have not been given proper place in Periodic Table. Coinage and Alkali MetalsAlkali metals and coinage metals with different properties are placed in the same group. This defect has been replaced by placing them into two sub groups. Modern Periodic Law and Modern Periodic Table

Modern Periodic LawPhysical and chemical properties of the elements are periodic function of their atomic number. Mosely (1913) says that atomic mas is not fundamental property. Due to some defects present in Mendeleyv's periodic law, Mosely introduced the concept of anomic number for the elements.ExampleWhen isotopes were discovered, it was thought advisable to arrange the elements on basis of their atomic number instead o increasing atomic mases. Isotopes were needed different position in the Mendeleyv's periodic table. Hence Mendeleyv's periodic law was modified. Modern Periodic TableWhen Mendeleyv's periodic law was modified and new elements were discovered. This forcd the scientists to change Mendeleyv's periodic law.The electronic configuration of atoms also played an important role in he arrangement of the modern periodic law. This form of periodic table is called "Long form of Periodic Table" because it contains eighteen groups instead of eight but seven periods instead of twelve. Group I - The Alkali MetalsThe elements of group I are called "Alkali Metals". The word alkali is derived from an Arabic word meaning Ashes.Elements of Group I • Lithium

• Sodium • Potassium • Rubidium • Cesium • Francium Properties of Group I1. They are mono atomic.2. They exist in solid metallic state.3. Outer most shell of these elements is incomplete having one electron.4. Elements of this group are highly reactive.5. Elements of this group have large tendency to form compounds.6. Elements of this group are strongly electro-positive. Group II - The Alkaline Earth MetalsThe elements of group II are called Alkaline Earth Metals. These elements occur in nature as silicate mineral and their oxides and hydroxides are strongly basic. Therefore these elements are called Alkaline Earth Metals.Elements of Group II • Beryllium • Magnesium • Calcium • Strontium • Barium • Radium Chemistry....Chapter 3

ATOMIC STRUCTURE

Dalton's Atomic TheoryThe important postulates of Dalton's atomic theory are:1. All elements are composed of atoms. Atom is too small so that it could not be divided into further simpler components.

2. Atom cannot be destroyed or produced.3. Atoms of an element are similar in all respects. They have same mass and properties.4. Atoms of different elements combine in a definite simple ratio to produce compounds.

Discovery of ElectronA discharge tube is a glass tube. It has two electrode, a source of electric current and a vacuum pump.(Diagram)Sir William Crooks (1895 performed experiments by passing electric current through gas in the discharge tube at very low pressure. He observed that at 10-4 (-4 is power to 10) atmosphere pressure, shining rays are emitted from cathode. These rays were named cathode rays. Cathode rays are material particles as they have mass and momentum. Properties of Cathode RaysThe properties of these particles are given below:

1. These particles are emitted from cathode surface and move in straight line.2. The temperature of the object rises on which they fall.3. They produce shadow of opaque object placed in their path.4. These particles are deflected in electric and magnetic fields.5. These particles are deflected towards positive plate of electric field. Discovery of ProtonGold Stein (1886) observed that in addition to the cathode rays, another type of rays were present in the discharge tube. These rays travel in a direction opposite to cathode rays. These rays were named positive rays. By using perforated cathode in the discharge tube the properties of these rays can be studied. Positive rays are also composed of metered particles. The positive rays are not emitted from anode. They are produced by the ionization of residual gas molecules in the discharge tube. When cathode rays strike with gas molecule, electrons are removed and positive particles are produced. Properties of Positive Rays1. They are deflected towards negative plate of electric field. Therefore these rays carry positive charge.2. The mass of positive rays is equal to the mass of the gas enclosed in the discharge tube.3. The minimum mass of positive particles is equal to the mass of hydrogen ion (H+). These positive ions are called Protons.4. The charge on proton is equal to +1.602x10-19 Coulomb. (-19 is power of 10) Natural RadioactivityThe phenomenon in which certain elements emit radiation which can cause fogging of photographic plate is called natural radioactivity. The elements which omit these rays are called radioactive elements like Uranium, Thorium, Radium etc. There are about 40 radioactive elements. Henri Bequrel (1896) discovered radioactivity.Madam Curei also has valuable contribution in this field.In natural radioactivity nuclei of elements are broken and element converted to other elements. Natural radioactivity is nuclear property of the elements. Alpha Rays1. They are helium nuclei. They are doubly positively charged, He2+.2. They move with speed equal to the 1/10th of the velocity of the light.3. They cannot pass through thick-metal foil.4. They are very good ionizer of a gas.5. They affect the photographic plate. Beta Rays1. They are negatively charged.2. They move with the speed equal to the velocity of light.3. They can pass through a few millimeter thick metal sheets.4. They are good ionizer of a gas.5. They can affect the photographic plate. Gamma Rays1. They are electromagnetic radiations.2. They travel with speed equal to velocity of light.3. They carry no charge.4. They have high penetration power than alpha and beta rays.5. They are weak ionizer of gas.

Rutherford Experiment and Discovery of NucleusLord Rutherford (1911) and his coworkers performed an experiment. They bombarded a very thin, gold fail with Alpha particles from a radioactive source. They observed that most of the particles passed straight through the foil undeflected. But a few particles were deflected at different angles. One out of 4000 Alpha particles was deflected at an angle greater than 150.(Diagram) ConclusionFollowing conclusions were drawn from the Rutherford's Alpha Particles scattering experiment.1. The fact that majority of the particles went through the foil undeflected shows that most of the space occupied by an atom is empty.2. The deflection of a few particles over a wide angle of 150 degrees shows that these particles strike with heavy body having positive charge.3. The heavy positively charged central part of the atom is called nucleus.4. Nearly all of the mass of atom is concentrated in the nucleus.5. The size of the nucleus is very small as compared with the size of atom. Defects of Rutherford ModelRutherford model of an atom resembles our solar system. It has following defects:1. According to classical electromagnetic theory, electron being charged body will emit energy continuously. Thus the orbit of the revolving electron becomes smaller and smaller until it would fall into the nucleus and atomic structure would collapse.2. If revolving electron emits energy continuously then there should be a continuous spectrum but a line spectrum is obtained.(Diagram) Bohr's Atomic ModelNeil Bohr (1913) presented a model of atom which has removed the defects of Rutherford Model. This model was developed for hydrogen atom which has only proton in the nucleus and one electron is revolving around it. Postulates of Bohr's Atomic ModelThe main postulates of Bohr's Model are given below:1. Electrons revolve around the nucleus in a fixed orbit.2. As long as electron revolves in a fixed orbit it does not emit and absorb energy. Hence energy of electron remains constant.3. The orbit nearest to the nucleus is the first orbit and has lowest energy. When an electron absorbs energy it jumps from lower energy orbit to higher energy orbit. Energy is emitted in the form of radiations, when an electron jumps from higher energy orbit to lower energy orbit. The unit of energy emitted in the form of radiations is called quantum. It explains the formation of atomic spectrum.4. The change in energy is related with the quantum of radiation by the equation :E2 - E1 = hvwhereE1 = Energy of first orbitE2 = Energy of the second orbith = Planck's constantv = Frequency of radiation Atomic NumberThe number of protons present in the nucleus of an atom is called atomic number or proton

number. It is denoted by z. The proton in the nucleus of an atom is equal to number of electrons revolving around its nucleus. Mass NumberThe total number of the protons and neutrons present in the nucleus of an atom is called mass number. The protons and neutrons together are called nucleon. Hence it is also known as nucleon number. It is denoted by A. the number of neutrons present in the nucleus of an atom is rperesented by N. Mass Number = No of Protons + No of neutronsA = Z + N IsotopesThe atoms of same elements which have same atomic number but different mas number are called Isotopes. The number of protons present in the nucleus of an atom remains the same but number of neutrons may differ. Isotopes of Different ElementsIsotopes of HydrogenHydrogen has three isotopes:1. Ordinary Hydrogen or Protium, H.2. Heavy Hydrogen or Deutrium, D.3. Radioactive Hydrogen or Tritium, T. ProtiumOrdinary naturally occurring hydrogen contains the largest percentage of protium. It is denoted by symbol H. It has one proton in its nucleus and one electron revolve around the nucleus. • Number of Protons = 1 • Number of Electrons = 1 • Number of Neutrons = 0 • Atomic Number = 1 • Mass Number = 1

DeutriumDeutrium is called heavy hydrogen. The percentage of deutrium in naturally occuring hydrogen is about 0.0015%. It has one proton and one neutron in its nucleus. It has one electron revolving around its nucleus. It is denoted by symbol D. • Number of Proton = 1 • Number of Electron = 1 • Number of Neutrons = 1 • Atomic Number = 1 • Mass Number = 2

TritiumRadioactive hydrogen is called tritium. It is denoted by symbol T. The number of tritium isotope is one in ten millions. It has one proton and 2 neutrons in its nucleus. It has one electron revolving around its nucleus. • Number of Proton = 1 • Number of Electron = 1 • Number of Neutron = 2

• Atomic Number = 1 • Mass Number = 3 Physics....Chapter 5

FORCE AND MOTION.

DYNAMICS"It is the branch of Physics which deals with causes of motion and their effects"

LAW OF MOTIONSNewton formulated three laws of motion in his book. NEWTON FIRST LAW OF MOTIONSNewton's first law of motion is also known as the Law of Inertia. STATEMENT"Every body continues its state of rest or uniform motion in a straight path until it is acted upon by an external, or unbalance force to change its state of rest or uniform motion". EXPLANATIONThis law consists of a two parts(a) When body is at rest(b) When body is moving with uniform velocity

When Body is At RestNewton's Law states that when a body is at rest, it continues its rest unless we apply a force on it. When we apply a force, it changes its state of rest and starts moving along a straight line. When Body is in MotionNewton's Law states that when a body is moving, it moves in a straight line with uniform velocity, but when we apply an opposite force, it changes its state of motion and come to rest.Examples• A body riding a push-bike along a leveled road does not come to rest immediately when we apply a force, it changes its state of rest and starts moving along a straight line. • If a bus suddenly starts moving, the passengers standing in the bus will fall in the backward direction. It is due to the reason that the lower part of the passengers which is in contract with the floor of the bus is carried forward by the motion of the bus, but the upper part of the body remains at rest due to inertia and so the passengers fall in backward direction. SECOND LAW OF MOTIONSSTATEMENT"When a force acts on an object it produces an acceleration which is directly proportion to the amount of the force and inversely proportional to the product of mass"

EXPLANATIONIt is well known fact that if we push a body with greater force then its velocity increases and change of velocity takes place in the direction of the force. If we apply a certain force F on a mass m, then it moves with certain velocity in the direction of the force. If the force becomes twice then its velocity will also increase two times. In this way if we go on increasing the fore there will be increase in velocity, which will increase the acceleration. DERIVATIONAccording to the Newton`s Second law of motion when a force acts on an object it produces an

acceleration which is directly proportion to the amount of the force.a < F { here < is the sign of directly proportional : Do not write this sentence in examination }and inversely proportional to the product of mass a < 1/m Combining all:. a < F/m a = K F/m If the Value of K is 1 so, a = F/m or F = ma 1, FORCEForce is an agent which produces motion in a body but some time force may not be succeeded to produce motion in a body so we can say that the force is an agent which produces or tends to produce motion in a body.We can further say that:Force is an agent which stops or tends to stop the motion of a body. In simple word we can also say that force is an agent which changes or tends to change the sate of an object. 2. MASSThe quantity of matter contained in a body is called mass.

FORMULA F = ma m = F/a UNIT The unit of mass in M.K.S system is Kilograme (kg) 3. WEIGHTIt is a force with which earth attracts towards its centre is called weight. FORMULAW = mg UNIT The unit of weight in M.K.S system is Newton (N). THIRD LAW OF MOTION" To every action there is always an equal and opposite reaction " EXPLANATIONAccording to Newton's Law of Motion, we have: F(action) = - F(reaction The negative (-) sign indicates that the two forces are parallel but in the opposite direction. If we consider one of the interacting objects as A and the other as B, then according to the third law of motion: F(AB) = - F(BA) F(AB) represents the force exerted on A and F(BA) is the force exerted on B.Examples • We we walk on the ground, we push the ground backward and as a reaction the ground pushes us forward. Due to this reason we are able to move on the ground.

• If a book is placed on the table, it exerts some force on the table, which is equal to the weight of the book. The table as a reaction pushes the book upward. This is the reason thta the book is stationary on the table and it does not fall down. INERTIADefinition"Inertia is the tendency of a body to resist a change in its state."ExamplesCover a glass with a post card and place a coin on it. Now strike the post card swiftly with the nail of your finger. If the stroke has been made correctly, the postcard will be thrown away and the coin will drop in the glass. If a moving bus stops suddenly, the passenger standing in it feels a jerk in the forward direction. As a result he may fall. It is due to the fact that the lower part of the standing passengers comes to rest as the bus stops. But the upper portion remains in motion due to inertia. Physics...Chapter 8

WORK, ENERGY AND POWER.

Definitions1. Joule It is the work done by a force of one Newton when the body is displaced one meter. 2. ErgIt is the work done by a force of one Dyne when the body is displaced one centimeter. 3. Foot Pound (ft-lb) It is the work done by a force of one pound when the body is displaced one foot. 4. ForceIt is an agent that moves or tends to move or stops or tends to stop a body. 5. WattWatt is the unit of power that is equal to the quantity of 1 Joule work done in 1 second. WorkWhen a force produces displacement in a body, it is said to do work.Units of Work• S.I System - Joule • C.G.S System - Erg ExplanationWhen force is applied in the direction of the displacement we can find the work by using definitionWork = Force * DisplacementW = F*sW = FsSuppose a man is pulling the grass cutting machine then the direction of the foce and displacement is not same. The applied force makes an angle @ with the ground while the motion takes place along the ground. In this case force is resolved into its components.Fx = Fcos@Fy = Fsin@As the machine moves along the ground, so Fx is doing the work, Hence:W = Force * Displacement

W = Fcos@*sW=Fscos@

EnergyEnergy is define as the capability to do work. Energy is also measured in Joules.Some Types of Energy• Potential Energy • Kinetic Energy • Chemical Energy • Heat Energy • Light Energy • Nuclear Energy Potential EnergyDefinitionThe energy possessed by a body due to its position is known as the Potential Energy of the body. It is represented by P.E. and is measured in Joules in System International.ExamplesThe energy of the following is potential energy:• A brick lying on the roof of a house. • The spring of a watch when wound up. • The compressed spring. • Water stored up in elevated reservoir in water-supply system. Mathematical ExpressionIf we lift a body of mass m to a height h, then the force applied on it is the its weight and it will act through a distance h.So,Work = Force * DistanceW = W * hSince W = mg, therefore:W = mg * hSince work is equal to energy possessed by a body:P.E. = mgh Kinetic EnergyDefinitionThe energy possessed by a body due to its motion is known as the Kinetic Energy of the body. It is represented by K.E.ExamplesThe energy of the following is kinetic energy:• A bullet fired from a gun. • A railway engine moving at high speed. • Motion of a simple pendulum. Physics...Chapter 9

MACHINES.

Definitions

1. MachineA machine is a device by means of which useful work can be performed conveniently and it can also transfer one form of energy into another form of energy.

2. Mechanical AdvantageThe ratio between the resistance or weight to the power applied in a machine is called the mechanical advantage of that machine. It is denoted by M.A.M.A. = Weight over-comed by Machine/ Force Applied on the Machine 3. Efficiency The ratio between the useful work done and the work done on the machine is called efficiency. M.A = (output/Input) * 100 4. InputInput is the work done on the machine. 5. OutputOutput is useful work done by the machine. LeverDefinitionLever is the simplest machine in the world. It is a rigid bar, which can be rotated about a fixed point. Principle of Lever In the lever the moment P acts opposite to that of work W. It means that force F tends to rotate the lever in one direction which the wight W rotates in opposite direction. If the magnitude of these moments acting in opposite direction is equal, then the lever will be in equilibrium. It means that:Moment of P = Moment of W Mechanical AdvantageWe know that according to Principle of Lever: Moment of P = Moment of W => Force * Force Arm = Weight * Weight Arm P * AB = W X BC AB/BC = W/P Hence, M.A = W/P = AB/BC = Weight Arm/ Force Arm Kinds of Lever1. First Kind of LeverIn the first kind of lever, the fulcrum F is in the between the effort P and Weight W.Examples• Physical Balance • Handle of Pump • Pair of Scissors • See Saw 2. Second Kind of LeverIn the second kind of lever, the weight W is in between the fulcrum F and effort P.Examples• Door • Nut Cracker

• Punching Machine 3. Third Kind of LeverIn the third kind of lever, the effortP is in between the fulcrum F and weight W.Examples• Human forearm • Upper and Lower Jaws in the Mouth. • A Pair of Forecepes Inclined PlaneDefinitionA heavy load can be lifted more easily by pulling it along a slope rather than by lifting in vertically. Such a slope is called an Inclined Plane.Mechanical AdvantageM.A = W/P = l/h = Length of Inclined Plane/Perpendicular Height

PulleyA pulley consists of a wheel mounted on an axle that is fixed to the framework called the block. The wheel can rotate freely in the block. The groove in the circumference prevents the string from slipping. Fixed PulleyIf the block of the pulley is fixed then it is called a fixed pulley.Mechanical Advantage of Fixed PulleyIn a fixed pulley, the force P is the applied force and weight W is lifted. If we neclect the force of friction then: Load = Effort In the given case: Load = W * Load Arm

Load = W * OB Also, Effort = P * Effort Arm Effort = P * OA So, W*OB = P*OA => W/P = OA/OB But, OA = OB, then M.A = W/P = OB/OB M.A = 1 Moveable PulleyIn this pulley, one end of the rope that is passing around the pulley is tied to a firm support and effort P is applied from its other end. The load and weight to be lifted is hung from the hook of block. In this system, the pulley can move. Such a pulley is called moveable pulley.Mechanical Advantage of Moveable PulleyIn an ideal system of a moveable pulley, the tension in each segment of the rope is equal to the applied effort. As two segments support the weight, the ffort acting on the weight W is 2P. Therefore, according to the principle of lever: W * Radius of the Wheel = 2P * Radius of the Wheel

=> 2P = W The Mechanical Advantage is given by: M.A = W/P M.A = 2P/P => M.A = 2Hence, the mechanical advantage of a moveable pulley is 2. Physics...Chapter 10

MATTER.

Definition of Matter "Anything having mass and volume is called matter."

Kinetic Molecular Theory of MatterThe Kinetic Molecular Theory of Matter has the following postulates:• Matter is made up of very small particles called molecules. • These molecules are in the same state of motion, hence they possess kinetic energy. Their motion can be translatory, vibratory or rotational. • The molecules attract each other with a force. This force depends upon the distance between them. Force is inversely proportional to the distance between the molecules. • When a substance is heated its temperature as well as molecular motion increases. Due to this motion, kinetic energy also increases. we can say that when the kinetic energy of the molecules increases, then temperature of the substance rises.

Brownian MotionIn 1827, a scientist, Robert Brown observed the motion of molecules with the help of a microscope. He observed that the tiny particles in water are constantly moving in a zigzag path. He called the motion, Brownian Motion.ExplanationThe cause of this tiny particle motion is the rapid motion of the molecules, which collide with the particles and push them in one direction. If some molecules come from other direction and collide with the same particles, particles change their direction. This process continues and the motion becomes zigzag.

States of MatterMatter has been classified into three states. These states are discussed below: 1.SolidAccording to the kinetic theory of matter, solid has the least kinetic energy. The properties of solids are given below:• The particles are very close to each other. • Their shape and volume is fixed. • Particles in a solid vibrate to and fro from their mean position. • On heating they melt and convert into liquid. • Some solids also convert directly into gas on heating. 2. LiquidAccording to the kinetic theory of matter, liquids have the following properties;• They have greater kinetic energy than solids but less than that of gases.

• The volume of liquid is fixed. • They move more freely than solids. • The attraction between molecules is lower than solids. • The distance between the molecules is greater than that of solids. • On heating, they convert into vapours. • On cooling, they convert into solid. 3. GasAccording to the kinetic molecular theory, gases possess the following properties.• Gases possess more kinetic energy. • Their shape and volume are not fixed. • The distance between their molecules is large. • Their temperature is proportional to their kinetic energy. • Their temperature rises with increase in pressure. • On cooling, they convert into liquid and gases. ElasticityDefinition" The tendency of a material to return to its original dimension after the deforming stress has been removed is known as elasticity."If we apply a force to a body, it is stretched. When the applied force is remove, the body returns to its original shape. The phenomenon of turning back to its original shape is called Elasticity. Elastic Behaviour and Molecular TheoryThe elastic behaviour of a material can be explained by the Kinetic Theory of Matter. Since the molecules in a solid are very close to each other, there exist strong attracting forces between them. Thus when force is removed, the attraction forces between the molecules pull them back again and the material is restored to its original shape. Different material have different elasticity depending on the nature of the material. Elastic LimitThe maximum resisting force of a material is called the Elastic Limit of that material. StressDefinition"When a body is made to change its length, volume or shape by the application of an external force, the opposing force per unit area is called Stress."FormulaStress = Force / Areao = F/A (Here o represents (Rho) do not write in your examination paper) Units• S.I or MKS System - N/m2 or Pascal (Pa) • C.G.S system - Dyne/cm2 • F.P.S or B.E System - lb/ft2 and lb/in2 (Here 2 in all above systems shows square) Types of StressFollowing are some types of stress:1. Tensile Stress: It is a stress tending to stretch a body.2. Bulk Stress: It is an overall force per unit area, also known as pressure.3. Shear Stress: It is a stress tending to produce an angular deformation. Physics...Chapter 11

HEAT.

Definitions1. Internal EnergyInternal Energy of a body is the sum of all kinetic and potential energy of all molecules constituting the body. 2. JoulesIt is the amount of heat required to rise the temperature of 1/4200 kg of pure water from 14.5 C to 15.5 C. 3. CalorieIt is the amount of heat required to rise the temperature of 1 g of pure water from 14.5C to 15.5C. 4. British Thermal UnitIt is the amount of heat tht is required to rise the temperature of 1 pound of pure water from 63F to 64F. Difference Between Heat and TemperatureHeat• Heat is the energy in transit from one body to another due to temperature difference. • It is the total kinetic energy of the body. • Heat is measured using Joule meter. • Its unit is Joule.

Temperature• Temperature is the degree of hotness or coldness of a body. • It is the average kinetic energy of the body. • Temperature is measured using thermometer. • Its units are F, C and K.

Thermal Expansionchange in length, breadth and height of a body due to heating is known as Thermal Expansion. It occurs in all the three states, i.e. solids, liquids and gases. Thermal Expansion of SolidsSolids expand on heating. Their ability to expand depends on their molecular structure. As the temperature is increased, the average kinetic energy of the molecules increases and they vibrate with larger amplitudes. This results in increase in the distance between them. Hence, they expand on heating. Thermal Expansion of solids can be classified into three types.

1. Linear Thermal ExpansionChange in length or any one dimension of a solid on heating is known as LInear Thermal Expansion. 2. Real ExpansionThe sum of the observed increase in the volume of a liquid and that of the containing vessel is called real Thermal expansion.Real Expansion = Apparent Expansion + Expansion of the Vessel 3. Apparent Expansion

Apparent Expansion is the expansion in which only the expansion of liquid is considered and expansion of the vessel is not taken into account. Apparent expansion is less the real expansion. Anomalous Expansion of WaterThe increase in the volume of water as its temperature is lowered from 4 C to 0C is known as anomalous expansion of water. Effects of Anomalous Expansion of Water1. In winter, the temperature in the north and south poles of the earth falls. As the temperature fall below 4 C water on the surface expands and stays afloat. Ice continues building up at the surface while the temperature at the bottom remains at 4 C. This helps fish and other forms of marine life to live.2. During the rainy season a lot of water seeps through the cracks in the rocks. In winter, when the water expands, the rock get broken due to this expansion.3. In cold climate, water supply pipes burst when the water expands on cooling. GAS LAWS1. Boyle's LawThe volume of a given mass of a gas is inversely proportional to the pressure, If the temperature is kept constant. P < 1/V (Here < represents sign of proportionality. Do not write this in your examination paper) P = C * 1/V C = PV The above equation is known as equation of Boyle's Law.

==2. Charle's Law The volume of a given mass of a gas is directly proportional to the temperature, if the pressure is kept constant. V < T (Here < represents sign of proportionality. Do not write this in your examination paper) V = C * T C = V/T The above equation is known as equation of Charle's Law. 3. Pressure LawThe pressure of a given mass of a gas is directly proportional to the temperature, if the volume is kept constant. P < T P = C * T

C = P/T The above is known as the equation of the Pressure Law. THERMOMETERThe instrument that is used to measure temperature is called a thermometer. Types of Thermometer1. Ordinary Liquid-in-Glass ThermometerIntroductionAn ordinary liquid-in-glass thermometer is used in a laboratory to measure temperature within a range of -10C to 110C. ConstructionIt consists of a glass stem with a capillary tube, having a small bulb at one end. This bulb is filled

with a liquid, usually mercury or alcohol coloured with a red dye. The upper end of the capillary tube is sealed so that the liquid will neither spill not evaporate. The air from the capillary tube is also removed. WorkingWhen the bulb is heated, the liquid in it expands and rises in the tube. A temperature scale is marked on the glass stem to indicate temperatures according to the various levels of liquid in the tube. 2. Clinical ThermometerIntroductionA clinical thermometer is a device that is used to find the temperature of the human body. It has a range from 35 C to 43 C (95F to 110F). ConstructionIt consists of a glass stem with a capillary tube, having a small bulb at one end. This bulb is filled with a liquid usually mercury or alcohol colored with a red dye. The upper end of the capillary tube is sealed so that the liquid will neither spill nor evaporate. The air from the capillary tube is also removed. The glass stem of a clinical thermometer has a construction in its capillary tube near the bulb. This helps to stop the mercury thread from moving back when the thermometer is removed from the patient's mouth. Physics...Chapter 12

WAVES AND SOUND.

Definitions1. VibrationOne complete round trip of a simple harmonic motion is called vibration.orIf a body in periodic motion moves to and fro over the same path, this motion is called Oscillation.2. Time Period (T)The time required to complete vibration is known as time period. 3. FrequencyIt is the number of vibrations executed by an oscillating body in one second. 4. DisplacementIt is the distance of a vibrating body at any instant from the equilibrium position. 5. AmplitudeThe maximum distance of the body on either side of its equilibrium position is known as amplitude. 6. Wave LengthThe distance between two consecutive crests and troughs is called wavelength. 7. Natural FrequencyThe frequency at which an object will vibrate freely (without any external periodic force or resistance) is known as natural frequency of that object. 8. Audible SoundOur ear can hear only those sounds whose frequency is between 20Hz and 20000Hz. This range is known as audible sound. 9. Ultrasonic Sound

Sound with frequency greater than 20000 Hz is known as ultrasonic sound. 10. OctaveThe interval between a waveform and another of twice the frequency is known as Octave. UnitsFrequency: Cycles per second (eps) or Hertz (hz)Wavelength: MeterIntensity of Sound: Watt/meter2 or W/m2Noise: Decibel (DB) Simple Harmonic Motion (S.H.M)Definition"To and fro motion of a body in which acceleration is directly proportional to displacement and always directed towards mean position is known as Simple Harmonic Motion." Condition for S.H.MThe conditions for simple Harmonic Motion are given below:• Some resisting force must act upon the body. • Acceleration must be directly proportional to the displacement. • Acceleration should be directed towards mean position. • System should be elastic.ExamplesFollowing are the examples of S.H.M:• Body attached to a spring horizontally on an ideal smooth surface. • Motion of a simple and compound pendulum. • Motion of a swing. • Motion of the projection of a body in a circle with uniform circular motion. ResonanceDefinition"The large amplitude vibration of an object when given impulses at its natural frequency is known as Resonance."ExperimentConsider a long string stretched tightly between two pegs. Four pendulums A, B, C and D of different lengths are fastened to the string. Another pendulum E of same length as A is also fastened.When pendulum E is set to vibrate, it will be observed that all the pendulums start to swing but pendulum A begins to vibrate with larger amplitude, as pendulum E is set into vibration. It imparts its motion to the string. This string in turn imparts the same periodic motion to the pendulums. The natural frequency of all other pendulums except A is different. Due to the same natural frequency only A vibrates as the same vibration of E. This phenomenon under which pendulum A begin to vibrate is called resonance.ExampleMarch of Soldiers while Crossing the BridgeEach bridge has its own natural frequency and marching of soldiers is another vibrating system. So there may occur a force on vibration in bridge. This may damage the bridge. So, for safely precautions, it is written that soldiers must march out of stop while crossing the bridge. WaveDefinition" A method of energy transfer involving some form of vibration is known as a wave."

Wave MotionWave motion is a form of disturbance, which travels through a medium due to periodic motion of particles of the medium about their mean position.ExperimentWe see that if we dip a pencil into a tap of water and take it out a pronounced circular ripple is set up on the water surface and travels towards the edges of the tub. However if we dip the pencil and take it out many times, a number of ripples will be formed one after the other.Waves can also be produced on very long ropes. If one end of the rope is fixed and the other end is given sudden up and down jerk, a pulse-shaped wave is formed which travels along the rope. Transverse WaveDefinition"The wave in which amplitude is perpendicular to the direction of wave motion is known as Transverse Wave."Examples• Radio Waves • Light Waves • Micro Waves • Waves in Water • Waves in String Longitudinal WaveDefinition"The wave in which amplitude is parallel to wave motion is called longitudinal wave."Example• Sound Waves • Seismic Waves SoundDefinition"A vibration transmitted by air or other medium in the form of alternate compressions and rarefactions of the medium is known as Sound." Production of SoundSound is produced by a vibrating body like a drum, bell, etc, when a body vibrates. due to the to and fro motion of the drum, compressions and rarefactions are produced and transmitted or propagated in air. Propagation of Sound WavesWhen a body vibrates in air, it produces longitudinal waves by compressions and rarefactions. These compressions and rarefactions are traveled by the particles of the medium and transferred into the next particles. Due to this transference, sound propagates in a medium.Experiment(Diagram)Suspend an electric bell in a jar by its wires through a cork fixed in its mouth. Switch on the bell, we will hear the sound of the bell. Now start removing air from jar with the help of an exhaust (vacuum) pump. The sound will decrease, although the hammer is still seen striking the bell. This experiment shows that air or any other medium is necessary for the propagation of sound. Velocity of SoundIt is a matter of common experience that the flash of lightning is seen earlier than hearing the thunder of cloud. Similarly when a gun is fired its sound is heard a little after seeing its flash.

The reason is that light is faster than sound. Due to its slow velocity sound lags behind.ExperimentSelect two stations at a distance of 8 km (or any more distance) such that there is no obstacle between them. Fire a gun at station A and note the time of sound taken for such distance. Repeat the process and note the time taken by the sound to travel from B to A. If we substitute the mean of the two times recorded and distance S (8km) in the formula V = S/t, we will get the velocity of sound. Factors Effecting Velocity of SoundThe factors are given below:• Velocity of air or any other medium. • Density of the medium. • Temperature of the medium. • Nature of the medium Characteristics of SoundThe characteristic properties of sound by which we can distinguish between noise and music, shrill and grave sounds or sound of men and women are known as characteristics of sound. The properties of sound are given below: 1.LoudnessDefinition"Loudness is the magnitude of auditory sensation produce by sound."Intensity can be defined as the energy carried by the sound waves through a unit area placed perpendicular to the direction of waver per second. Factors Effecting Loudness of SoundLoudness depend on following factors:Area of Vibration of Body: Greater will be the surface area more will be the loudness. Amplitude of Motion of Vibrating Object: Greater will be the amplitude, more will be the loudness. Density of Medium: Loudness is directly proportional to the density of medium. Motion and Direction: If source of sound is moving towards the listener loudness will be greater or if wind supports the velocity of sound the loudness will be greater.

2. PitchDefinition"The sensation that a sound produces in a listener as a result of its frequency is known as Pitch."This is the property of sound by virtue of which we can distinguish between a shrill and grave sound. Factors Effecting Pitch of SoundPitch depends on following factors:• Frequency of Vibrating Body: The greater the fundamental frequency, more shrill will be the sound. • Relative Motion of Sound: If source and listener both are coming closer pitch will increase.

3. Quality or Timbre or Tone Definition"The characteristic of a musical note that is determined by the frequency present is known as Quality or Timbre or Tone of that sound."

This is the property of sound by virtue of which it is possible to identify a sound of the same loudness and pitch but originating from different instrument. Factors Effecting QualityQuality depends upon the following factors:• Phase of the Sound Wave. • Shape of Waves

Harmful Effects of Sound (Noise)Nowadays noise is considered as a great pollution, which is very dangerous for us. Some of them are as follows:• Continuous noise damages hearing and can result in complete deafness. • Noise has become a great cause for depression and blood pressure. • Mental system shows less efficiency due to noise. • Consequently it is harmful in all respects for living body.

Musical SoundThe sound producing pleasing effect on our ears are called musical sounds. Difference Between Longitudinal and Transverse WavesLongitudinal Waves1. In longitudinal waves, particles of the medium vibrate in the direction of the waves.2. The portion of wave in which particles of medium are very close to each other is called compression.3. Examples of longitudinal waves are sound wave and seismic waves.4. Distance between the centre of two compressions and rarefactions is called wavelength. Transverse Waves1. In transverse waves, particles of the medium vibrate in the direction perpendicular to the direction of wave.2. The portion in which particles of medium are higher than their normal position is called crest.3. Examples of transverse wave are microwaves and radio waves.4. Distance between two crests and troughs is called wavelength. Physics....Chapter 13

PROPAGATION AND REFLECTION OF LIGHT .

Definitions1. Incident RayThe ray that strikes the surface of the medium is known as Incident Ray.

2. Reflected RayThe ray that is sent back into the same medium after reflection is known as reflected ray. 3. Plane MirrorA flat smooth reflecting surface, which shows regular reflection is known as plane mirror. 4. NormalPerpendicular line on the reflecting surface is known as normal. 5. PoleThe centre of the spherical mirror is called pole.

6. Angle of IncidenceThe angle subtended by the incident ray to the normal is known as angle of incidence. 7. Angle of ReflectionThe angle subtended by the reflected ray to the normal is known as angle of reflection. 8. Center of ReflectionThe center of the hollow sphere of which the mirror is a part is called center of curvature. 9. Principle AxisThe straight line passing through center of curvature nad the pole is known as principle axis. 10. Principle FocusThe ray coming parallel to principal axis after converges to or diverges from a point, which is called principle focus. 11. Focal LengthThe distance between the principle focus and pole of the mirror is called Focal Length. 12. Radius of CurvatureThe distance between the center of curvature and the pole is called radius of curvature. 13. Real Image the image that can be seen on a screen is known as a real image. 14. Virtual ImageThe image that cannot be seen on a screen is known as a virtual image. 15. MagnificationThe ratio between the image height and object height is known as magnification. The ratio between the image distance to the object distance is known as magnification. Reflection of LightDefinition"The process in which light striking the surface of another medium bounces back in the same medium is known as Reflection of Light." Laws of Reflection1. The angle of reflection, is equal to the angle of incidence: n<i = m<r.2. The incident ray, reflected ray and normal, all lie in the same plane. Kinds of ReflectionThere are two types of Reflection: 1. Regular ReflectionDefinitionWhen parallel rays of light strike a surface and most of them are reflected in a same particular direction or same angle, they are said to be regularly reflected and the phenomenon is known as regular reflection.Regular reflection occurs when parallel rays of light strike with an ideal smooth plane surface. In regular reflection parallel rays remain parallel after reflection. 2. Irregular ReflectionDefinitionWhen some rays of light strikes a surface and the reflected rays scatter in different directions, this type of reflection is called irregular reflection.It occurs when parallel rays strike with an irregular rough surface. In this case rays does not remain parallel after reflection and they scattered. Advantages of Irregular Reflection• Due to this reflection, sunlight reaches us before sunrise and persists for some time even after

the sunset. • Due to this reflection we get sufficient light in our rooms and other places where sunlight do not reach directly. • Due to this reflection sunlight reaches to each of the leaves of a tree and photosynthesis takes place on large scale. • Due to this reflection, we can see luminous objects. Image Formed by a Plane MirrorConsider a mirror MM', AP is an object. Consider that a point P lies on the tip of the object. From P as ray travels and strikes mirror and reflect back to the eye, they appear to come back. From Point P' as shown in the figure. Hence P' is the image of P. Similarly, infinite points lying an object produces infinite images of points and complete image of an object is formed. Characteristics of Image Formed by a Plane Mirror• Image is same in size as that of the object. • The distance of object and image are equal from the mirror. • The image formed is virtual and inverted. Spherical MirrorsDefinition"A spherical mirror is a section of a of a hollow sphere." Types of Spherical MirrorsThere are two types of spherical mirror:• Concave Mirror (Converging Mirror) • Convex Mirror (Diverging Mirror) 1. Concave MirrorDefinition"The spherical mirror in which inner side of the surface is polished for reflection is called a concave mirror."

Properties• The bulging side is polished. • Reflection occurs from its hollow side. • They converge the parallel rays at a point. • They can form real and imaginary, both types of images. 2. Convex MirrorDefinition"The spherical mirror in which inner side of the surface is polished for reflection is called concave mirror." Properties• The bulging side is polished. • Reflection occurs from its hollow side. • They converge the parallel rays at a point. • They can form real and imaginary, both type of images. Formation of Image by Concave MirrorsThere are six cases to form an image by concave mirror.

1. Object at Infinity(Diagram)

If the object is placed at infinity from the mirror, the rays coming from the object are parallel to principal axis. After reflection, they meet at principal focus and image is formed at the focus. Details of Image• Formed at F. • Extremely Small • Real • Inverted 2. Object Beyond C(Diagram)If the object is placed beyond C, rays coming from the object are not parallel. They meet after reflection between the focus and center of curvature. Therefore, image is formed between the focus and center of curvature. Details of Image• Formed between F and C. • Small in size. • Real • Inverted 3. Object at Center of Curvature 'C'When object is placed at the centre of curvature, the image formed at the same place.(Diagram)

Details of Image• Formed at C • Equal in size • Real • Inverted 4. Object Between F and C(Diagram)When the object is placed between the focus and Centre of curvature, the image is formed beyond the centre of curvature. Details of Image• Formed beyond C. • Large in size. • Real • Inverted 5. Object at F(Diagram)When object is placed at focus the reflected rays become parallel to each other. The two parallel lines meet at infinity. Therefore, we say the image is formed at infinity. Details of Image• Formed at Infinity. • Extremely Large • Real • Inverted 6. Object between P and F(Diagram)

For locating object between pole and focus the rays reflected do not meet because they diverge. But they meet backward. So, the image is formed backward or behind the mirror. Details of Image• Formed behind the mirror. • Large in size • Virtual • Erect Uses of Spherical MirrorSpherical mirrors are used in several places. Some of them are given below: • Shaving: A concave mirror is used to enlarge the image. • Microscope: A convex mirror is used for magnification in a microscope. • Telescope: The convex mirror is used. • In Searchlights and Headlights: Concave mirror is used to form the rays in searchlights and headlights, used for different purposes. • For Rear View: The convex mirror is used in automobiles. • In Medical Examination (Opthalmoscope): Doctors use concave mirror for the examination of ear, nose, throat and eyes of patients. Physics...Chapter 14

REFRACTION OF LIGHT AND OPTICAL INSTRUMENTS.

Definitions1. Emergent RayThe ray after passing the second medium comes again in the first medium. It is called emergent ray. 2. Emergence AngleThe angle formed by the emergent ray and normal is called emergence angle denoted by <e. 3. Optical CenterThe middle point of the lens is called optical center. The ray passing through this point does not bend. 4. AccommodationThe ability of the eye to change the focal length of its lens so as to form a clear image of an object on its retina is called is power of accommodation. 5. Persistence of VisionWhen an object is seen by an eye, its image forms on retina. If the object is removed, the impression of image persists in the eye for about 1/10 second. This interval is called Persistence of Vision. 6. Power of LensThe power of the lens is the reciprocal of the focal length measured in meter. Its unit is Dioptre. Refraction of LightDefinition"The change in the direction and velocity of light as it enters from one medium to another is known as Refraction of Light." Laws of Refraction• The incident ray, refracted ray and the normal at the point of incidence all lie in the same plane.

• The ratio of sine of angle of incidence (i) to the sine of angle of refraction (r) is constant for all

rays of light from one medium to another. This constant is known as Refractive Index (u). This ratio is also equal to the ratio of the speeds of light in one medium to another.Refractive Index = sin<i/sin<r = Speed of light in first medium/Speed of light in second medium

Refractive IndexThe ratio between the sine of the angle of incidence to the sine of angle of refraction is known as Refractive Index. Refractive Index = sin <i/sin<r

Snell's LawThe refractive index between two particular mediums is equal to the ratio of speed of light in first medium and speed of light in second medium equal to the ratio between sin <i and sin <r.Refractive Index = sin<i/sin<r = Speed of light in first medium/Speed of light in second medium PrismDefinition"Prism is a transparent piece of glass. It has three rectangular sides and two triangular sides. Refraction Through a Prism(Diagram)where,• <i = angle of incidence • <r = angle of refraction • <e = angle of emergence • <D = angle of deviation Total Internal Reflection(Diagram)If the value of angle of incidence is increased so much so that it becomes greater than tht of the critical angle then no more refraction occurs but on the other hand refracted ray again comes back in the denser medium. Actually at that time, the surface of denser medium acts as a plane mirror and the incident ray bends in the same medium. This phenomenon is called Total Internal Reflection. It is used in Periscope, Optical Fibers and other instruments. Total Reflecting PrismTotal internal reflection is used in prism. In prism the angle between two opposite sides is 90 and other two angles are 45 each. If we arrange a ray so that it falls perpendicular to the AB side then it will refract without bending and strike the side AC with angle 45. Then it totally reflects to the side BC. Conditions for Total Internal Reflection• The ray of light should travel from denser to rarer medium. • The angle of incidence should be greater than the critical angle. LensesDefinitionA transparent and smooth glass or any refracting medium surrounded by two spherical surfaces is known as lens. Types of LensesThere are two types of lenses: 1. Convex LensIf the glass is thick at the center and thin at the edges then it is known as convex lens. It is a

converging lens.(Diagram)It has three types:• Double Convex Lens • Plano Convex Lens • Concavo Convex Lens

2. Concave LensIf the lens is thinner in the center and thicker at the edges then it is known as a concave lens. It is a diverging lens.(Diagram)It has three types:• Double Concave Lens • Plano Concavo Lens • Convex Concave Lens Formation of Image by Convex Lens1. Object at InfinityWhen object is placed at infinite distance from convex lens the rays coming from the object are parallel to each other and they meet after refraction at the focus. Details of Image• Formed at Focus • Real •Inverted • At opposite side • Highly diminished 2. Object Beyond 2FWhen object is placed at some distance from 2F then image is formed between the focus and center of curvature (2F). Details of Image• Between F and 2F • Opposite side of Lens • Real • Inverted • Small in size 3. Object at 2FWhen object placed at center of curvature, image is formed at center of curvature at the opposite side. Details of Image• Real • Inverted • At 2F • Same in size • At the opposite side of the Lens Physics...Chapter 15

NATURE OF LIGHT AND ELECTROMAGNETIC SPECTRUM.

Definitions1. Dual Nature of LightLight has dual nature, it behaves not only as a particle (photon) but also as a wave. This is called dual nature of light. 2. Dispersion of LightWhen a beam of sunlight falls on a prism, the light is split up in seven colours. This phenomenon is called Dispersion of Light. 3. RainbowThe rainbow is an arc of spectral colours formed across the sky during or after rainfall in the morning or when the sun is behind us. 4. Photons (Quantum) Photons are tiny packets of energy. They behave as particles but actually they are not particles.

==Newton's Corpuscular Theory of Light==This theory which was proposed by Newton is as follows:• Light is emitted from a luminous body in the form of tiny particles called corpuscles. • The corpuscles travel with the velocity of light. • When corpuscles strike the retina they make it sense light. • Medium is necessary for the propagation of light. • Velocity of light is greater in denser medium.

Wave Theory of LightIn 1676, Huygen proposed this theory. According to this theory:• Light propagates in space in the form of waves. • It can travel in space as well as in a medium. • Light does not travel in a straight line but in sine wave form. • Velocity of light is greater in rarer medium. • Medium is not necessary for propagation. Quantum Theory of LighAccording to this theory of Max Plank:• Light is emitted from a source discontinuously in the form of bundles of energy called Photons or Quantum. • It travels in space as well as a medium. • Speed of light is greatest in space or vacuum. How A Rainbow is Formed?As we know a prism disperses sunlight into a series of seven colours. When rain falls, raindrops behave like a prism and white light entering the raindrop splits up into seven colours on refraction. These are appeared as Rainbow. SpectrumAfter the dispersion of light or any electromagnetic wave, a band of colours is formed, which is known as a spectrum. Electromagnetic SpectrumElectromagnetic spectrum is a result obtained when electromagnetic radiation is resolved into its constituent wavelength. Waves of Electromagnetic Spectrum

Radio WavesIt has a large range of wavelengths from a few millimeters to several meters. MicrowavesThese radio waves have shorter wavelength between 1mm and 300 mm. Microwaves are used in radars and ovens. Infrared WavesIt has a long range. Its mean wavelength is 10 micrometers. Visible WavesIt has a range of 400 nm to 700 nm. Ultraviolet WavesTheir wavelength ranges from 380nm onwards. These are emitted by hotter start (about 25000 C). Physics...Chapter 16

ELECTRICITY.

Definitions1. InsulatorsThose material objects that do not allow charge to pass through them are known as Insulators or non-conductors.

2. ConductorsThose material objects that allow the charge to pass through them are called conductors. 3. Semi ConductorsThose material objects that allow some charge to pass through them are called Semi-Conductors.

4. Free ElectronThose electrons that are loosely bound by their atom and can move freely within the material are called free electrons. 5. DielectricThe medium or space (vacuum) between two charges is said to be dielectric. 6. Force of AttractionWhen two charges attract each other the force is called force of attraction. It has a negative sign. 7. Force of RepulsionWhen two charges repel each other the force is called force of repulsion. It has a positive sign. 8. Equivalent ResistanceThe relative resistance that has equal value to the combined value of a resistor of a circuit is called equivalent resistance. It is denoted by R(E). 9. Direct CurrentSuch a current that does not change its direction is known as direct current. It is denoted by DC, which is obtained from primary and secondary cell.s 10. Alternating CurrentSuch a current that reverses its direction with a constant frequency from positive to negative and negative to positive direction is known as Alternating Current, obtained by generators. It is denoted by AC. 11. Conventional Current

An electric current considered to flow from points at positive terminal potential to points at negative potential. 12. Primary CellA voltaic cell in which the chemical reaction that produces the e.m.f is not reversible is known as Primary Cell. 13. Secondary CellAn electric cell that can be changed by passing an electric current through it is called Secondary Cell. The chemical reaction in this case is reversible. 14. Fused PlugIt is a wired plug, which has its own cartilage fuse. It is used in a ring main circuit. 15. Electric CircuitA combination of electrical components that form a conducting path is called an electric circuit. 16. Commercial Unit of Energy (kWh)1 kWh is the energy produced by a resistor or conductor in 1 hour when it uses 1000 Watt power.

17. WattIf 1 joule of electrical work is done in 1 second then the power is called 1 watt. Electrostatic InductionWhen a charged body brought close to another uncharged body then other body gains some chrge without any touch. This is called electrostatic induction. Gold Leaf ElectroscopeAn electroscope is a device that can be used for detection of charge. 'ConstructionIt consists of a glass case that contains two turn leaves of gold (Au) which are capable to diverge. The leaves are connected to a conductor to a metal ball or disk out side the case, but are insulated from the case itself.(Diagram) WorkingIf a charged object is brought close to the ball, a separation of charge is induced between the ball and gold leaves. The two leaves become charged and repel each other. If the ball is charged by touching the charged object the whole assembly of ball and leaves acquires the same charge. In either case greater the amount of charge greater would be the diverging in lens. Electrostatic PotentialA charged body place in electrostatic field as an electrostatic potential as earth has its gravitational potential. Potential DifferenceDefinition"The difference in electrostatic potential between two points in an electrostatic field is called potential difference."When a unit positive charge body moves against an electrical field from A to B, then work done has been stored as potential difference. Therefore, we say that"Potential difference is work done or energy stored per unit charge." Unit Since Potential Difference = Work Done/Charge

V = W/q Therefore, its unit is: V = Joules/Coulomb = J/C = Volt.

Volt 1 volt potential difference is equal to one joule work done on 1 coulomb charge. CapacitorIt is a device for string electric charge. It is a system of two (or more) plates on which we can store electric charge. Parallel Plate CapacitorIt is a simple capacitor with two parallel plates on which we store the electric charge.(Diagram) ConstructionA parallel plate capacitor has two metallic plates with their stands and a dielectric which is air or some insulator. E.g. wax paper, wax, oil and mica. Physics....Chapter 17

MAGNETISM AND ELECTROMAGNETISM.

Magnet Metals like iron, nickel and steel attract each other magnetically. They are called magnets and always point in a particular direction when suspended freely in the air. Non-Magnetic SubstancesSubstances that are neither attracted nor repelled by a magnet are called non-magnetic substances. Examples are wood, glass and paper. Ferromagnetic SubstancesA substance which behaves like a magnet in the presence of a strong magnetic field is called a ferromagnetic substance.. 1. Hard Ferromagnetic SubstancesThe ferromagnetic substances which retain their magnetism when removed from the magnetic field are known as hard ferromagnetic substances. Example is steel. 2. Soft Ferromagnetic SubstanceThe ferromagnetic substances which become magnets in the presence of a magnetic field and lose their magnetism when removed from the magnetic field are known as soft ferromagnetic substance. Example is soft iron. Magnetic FieldThe space surrounding a magnet in which its magnetic effect is felt is called a magnetic field. It is the region within which the magnet can exert its magnetic force. Methods of Making Magnets1. Single-Touch MethodTake a hard steel bra and rub it with one end of a magnet in the direction from S to N, keeping the magnet in an inclined position. On reaching the end N of the steel bar, bring the same end of the magnet to the end S of the steel bra and rub it again. Repeat the process several times and the steel bar will be magnetized. The end S will have the same polarity as that of the rubbing pole of the magnet and the end N will have the polarity opposite to that of the rubbing pole. 2. Electrical Method

Take a U-shape steel bar and wound it with an insulated copper wire making sure that the two core arms are wound in the opposite directions. Connect the coil to a battery and pass strong current. The steel bar becomes a magnet as long as current passes through them. In a similar way, a bar can be magnetized by putting it inside a solenoid and passing current through the solenoid. The polarity of the magnet is determined by the direction of the current. DemagnetizationThere are three methods for demagnetizing magnets. 1.HammeringMagnets can be partially demagnetized by hammering them when they are pointing in the east or west direction. 2. HeatingMagnets loose their magnetism when they are heated strongly. 3. Electrical MethodThe most efficient method of demagnetizing a magnet is to use n alternating current. Take a solenoid and place it in the east west direction. Pass an alternating current (about 12 V) through it. Now, put the magnet in the solenoid from one end and pull it out from the other. While the current is still flowing. The magnet will loose its magnetism.Alternating current reverses its direction at a rate of 100 times per second and hence causes the magnetism of the material to reverse the polarity at the same rate. Due to this rapid reverse in the polarity, the magnet looses its magnetism. Magnetic Effect of CurrentWhen an electric current passes through a straight wire a magnetic field is created which consists of field lines in concentric in concentric circles with the wire at their center. Right Hand RuleThe direction of the magnetic field can be determined by the following rule:"Imagine the wire to be grasped in the right hand with the thumb pointing along the wire. The direction of the fingers will give me direction of the magnetic lines of force." SolenoidA coil of insulated copper wire in the form of a long cylinder is called a solenoid. Magnetic Field of a SolenoidWhen an electric current is passed through a solenoid a magnetic field is produced which is very similar to that of a bar magnet. One end of the solenoid acts as the north pole and the other as the south pole. The magnetic field inside a solenoid is very strong because the lines of force are parallel and close to one another. The magnetic field outside the solenoid is very weak. ElectromagnetIf soft iron is inserted in the core of a solenoid, the magnetic field due to the current in the solenoid is multiplied by thousands. When the current is switched off, the magnetic field disappears. Such a magnet which can be energized by an electric current is called an electromagnet. Applications of ElectromagnetsIndustryThey are used to transport heavy pieces of iron and steel safely from one place to another. With the help of electromagnets, iron from mixture is separated.They are used to produce strong magnetic fields for high power motors and generators. 1. Electric BellConstruction

An electric bell consists of an electromagnet. One end of the winding is connected to a terminal (T1). The other end is connected to a spring, which is mounted on a soft iron strip called "Armature." A rod is attached to the armature with its free end having a small hammer that can strike against the bell. a very light spring is attached to a contract adjusting screw which is joined to the second terminal (T2) by a wire. The electric circuit is completed by connecting the terminals to a batter and a switch.(Diagram) WorkingWhen the push button switch is pressed, the circuit gets closed and the armature is attracted towards the electromagnet. The spring also gets detatched from the screw. This results in opening the circuit and the electromagnet gets demagnetized. The attraction disappears bringing back the spring to its original position. As soon as the spring touches the screw, the circuit gets closed and the magnet starts to work. It again attracts the armature and this process is repeated as long as the switch is turned on. As a result, the armature vibrates and hammer attached to it strikes the gong. Hence, the bell rings. 2. Telephone ReceiverIntroductionA telephone receiver is a device that converts electrical energy into sound energy. ConstructionThe ear piece consists of a permanent magnet in contrast with two electromagnets. A diaphragm of magnetic alloy is positioned in front of the electromagnets. WorkingWhen the message is transmitted from the other apparatus, sound energy is converted into electric current and is transported to the ear piece through the line. This electric current varies in magnitude depending upon the frequency of the sound waves. In the telephone receiver, the current passes through the electromagnet and energizes the magnet. In this way, the magnetic field strength varies as the current changes. The magnetic force that pulls the diaphragm also varies accordingly. The diaphragm therefore vibrates and gives rise to sound of the same frequency as spoken at the other end. Fleming's Left Hand Rule"Place the fore finger and the second finger of the left hand at right angles. Then, if the fore finger points in the direction of the magnetic field and the second finger in the direction of the current, then the thumb will point in the direction of the motion." GalvanometerIntroductionA galvanometer is a sensitive and delicate device used to measure the magnitude and direction of small currents. Principle of GalvanometerThe principle of Galvanometer is based on the interaction of the magnetic field produced by a current forcing in a conductor and the magnetic field of permanent magnet. In this instrument, electrical energy is converted into mechanical energy. ConstructionA rectangular coil of wire is wound on a light frame with a pointer attached on the top. The coil frame is pivoted between the jaws of a large horseshoe magnet. At both ends of the coil, hairsprings are attached. These springs help in keeping the coil at zero potential and also provide the path for entry and exit to the current. A soft iron cylinder is fixed in the core of the coil to

enhance the force of conductor. The concave shape of the poles of the horseshoe magnet combined with the cylindrical shape of the core creates the radial field to ensure that the field lines are always perpendicular to the coil. WorkingWhen current passes through the coil a couple of opposite forces are produced and causes the coil to rotate. By the motion of the coil, pointer moves on the scale and galvanometer is used to determine the magnitude and direction of current. AmmeterIntroductionA galvanometer having a low resistance in parallel is called as ammeter. It is used to measure current. The low resistance connected in parallel is called shunt. WorkingWhen current is passed through a Galvanometer, its coil is deflected and pointer attached with the coil moves over a scale. The range for the measurement of current in a galvanometer is very small. Therefore, a low resistance in parallel is used with a galvanometer. This resistance by passes a great part of the current. Only a small amount of current passes through the galvanometer coil, which is within the range of the galvanometer. This resistance acts as a shunt. An ammeter is always placed in series with other circuit components through which current is to be measured. VoltmeterIntroductionA galvanometer having high resistance in series is called a voltmeter. It is used to measure potential difference. WorkingThe potential difference across a resistance is directly proportional to the current passing through it. As the deflection of the pointer is directly proportional to the current, therefore the deflection of the pointer is directly proportional to the potential difference. A small potential difference produces a full-scale deflection in a galvanometer. In order to measure high potential difference, a high resistance is connected in series with the galvanometer. Most of the potential difference drops across the high resistance. The value of resistor connected in series depends upon the range of the voltmeter. In order to measure the potential difference, a voltmeter is always connected in parallel to the circuit components. Physics...Chapter 18

ELECTRONICS.

Definitions1. Electronics

Electronics is a branch of Physics, which deals with the development of electron emitting devices, their utilization and controlling electron flow in electrical circuits designed for various

purposes. 2. Semi ConductorSubstances whose electrical resistance lies between those of conductors and insulators are known

as semi-conductors. 3. Doping

Mixing of any tetravalent element into a trivalent or pentavalent element so that its electrical conductivity increases is called dopping.

4. n-Type SubstanceA pure semiconductor with a valency of three, doped with a pentavalent element is called n-type

semiconductor. 5. p-Type Substance

A pure semiconductor with a valency of three doped with a trivalent element is called n-type semiconductor.

6. DiodeThe common boundary of n-type and p-type regions in a semiconductor is called p-n junction

diode. It allows the current to flow in only one direction. 7. Forward Biased

If the p-type material of a semi conductor diode is at a positive potential and the n-type material is at a negative potential then the diode is forward biased. It has a very low electrical resistance.

8. Reverse BiasedIf the p-type material of a semi-conductor diode is at a negative potential and the n-type material is at a positive potential then the diode is reverse biased. It has a very high electrical resistance.

9. RectificationThe process of conversion of alternating current into direct current is known as rectification.

10. RectifierA rectifier is a device that converts Alternating current into Direct current.

11. TransistorA transistor is a semiconductor, which consists of a thin central layer of one type of

semiconductor material sandwiched between two relatively thick pieces of the other type of semiconductor. The central part is known as the base (b) and the pieces at either side are called

the emitter (e) and the collector (c). 12. npn Transistor

The npn transistor has a thin piece of p-type substance sandwiched between two pieces of n-type semiconductors.

13. pnp TransistorThe pnp transistor has a thin piece of n-type substance sandwiched between two pieces of p-type

semiconductors. Telegraph

IntroductionA telegraph is a device that is used to send and receive messages between two distant points.

ConstructionAn electric telegraph consists of a battery that is connected to a buzzer through the tapping key.

There is only one wire between the buzzer and the tapping key. The circuit is completed by connecting the other terminal to the ground few feet below. The earth being moist acts as a good

conductor. Working

When the tapping key is pressed, the receiver produces a buzzing sound. The interval between two buzzing sounds can be controlled by the interval between pressing the tapping key. The

international Morse Code, which is a combination of dots and dashes is used to send and receive messages with the help of telegraph.

RadioIntroduction

A radio is a device for receiving and sending speech or music over large areas by

electromagnetic signals. Working

1. Transmission: Information is sent out into the atmosphere from a transmitting station. When someone speaks in the microphone at the radio station, sound waves are converted into electrical

fluctuating current. This current is converted into high frequency alternating current, which is allowed to pass in the transmitting antenna. The transmitting antenna produces radio waves with

fluctuating amplitude. These waves are known as modulated carrier waves.

2. Receiving: When the modulated carrier waves meet a receiving aerial, they generate fluctuating alternating current in it. This AC is converted into DC with the help of a rectifier. An

earphone or a speaker is connected to the receiver. The DC energizes the electromagnet of the speaker and causes the diaphragm to vibrate. This produces the sound of same frequency as that

at the radio station. Radar

IntroductionRadar stands for Radio Detection and Ranging. It is used to detect and find out the distance of

distant object with the help of radio waves. Construction

It consists of a transmitter, a receiver and several indicating devices. Working

1. Transmission: The transmitter generates very high frequency electromagnetic waves in the desired direction with the help of a concave antenna.

2. Receiving: These rays after striking an object are reflected back and are received by the radar antenna. The antenna feeds these rays in the indicating devices.

3. Processing: The indicating devices measure the time taken by the waves to return. They calculate the wave velocity and finally the distance of the object.

Radar waves can penetrate fog, clouds, haze and smoke. Telephone

IntroductionA telephone is a device by which two persons at distant places can directly talk to each other

through electric current carrying wires. Construction

A telephone system consists of a microphone and a receiver. 1. Microphone: The microphone consists of a diaphragm suspended in front of packing of

carbon granules. 2. Receiver: The receiver has an electromagnet and a diaphragm made of magnetic alloy in front

of it. Working

1. Transmission: When someone speaks in front of the microphone, the diaphragm vibrates due to the sound waves. The compressions and rarefactions of the sound waves cause the diaphragm

to increase and decrease the pressure on carbon granules. This results in the increment and decrement in the resistance offered by the granules and hence generates fluctuating current.

2. Receiving: At the receiver, the electromagnet receives fluctuating current, which generates a fluctuating magnetic field. The diaphragm in front of the electromagnet also vibrates with different amplitudes and generates sound of same frequency as spoken at the other end.

TV CameraWorking

For the purpose of TV Transmission, TV Camera focuses on object to be televised. The convex lens of the TV Camera produces an image on the thin sensitive plate known as mosaic screen. The mosaic screen is fixed in the camera and has the ability to emit electrons. When light is

stronger, more electrons are given out the material making positive at this location. The beam of electrons from the electron gun in the camera tube is meant for scanning the back surface of the mosaic screen along the successive longitudinal lines in it. Special magnetic deflection system

achieves this purpose. As soon as the beam hits on an area with high positive charge, few of the negative charges are repelled. If the positive charge is less, more of the electrons are emitted.

After the collection of these electrons it is converted into voltage pulse known as video signal. The video signals that have been amplified are utilized to manufacture very high frequency. This

frequency is received by a television antenna, which reverses the process and gives us a clear animated picture on the screen.

Physics...Chapter 19

NUCLEAR PHYSICS.

Nuclear PhysicsIt is the branch of Physics that deals with the structure, properties and reaction of particles found in the nuclei of atoms. RadioactivityThe phenomenon of emission of radiation from Uranium and other substances is known as radioactivity. The substances that emit radiation are known as radioactive elements. ExperimentA small quantity of a radioactive element such as radium is placed in a cavity of a lead block in such a way that the radiation from radium can only come out through this cavity. A photographic plate is placed at some distance above the lead block so that the radiation from radium falls upon it. The apparatus is placed in a vacuum light chamber which is evacuated by a powerful pump. This chamber is then placed between the poles of a powerful magnetic field. Under the action of magnetic field, two or three types of radiation are deflected forming three separate images on the photographic plate. Properties of Alpha Particles• Alpha particles are Helium nuclei. • The charge on alpha particles is positive. • The velocity of alpha particles is 1/100th of the velocity of light. • Ionization power is greates. • Penetration power is the least. • It effects the photographic plate. • It produces florescence with zinc sulphide solution. Properties of Beta Particles• Beta particles are fast moving electrons. • The charge on beta particles is negative. • Its velocity is slightly less than the velocity of light. • Ionization power is less than alpha particles. • Its penetration power is greater than alpha particles.

• It effects the photographic plate. • It produces florescence with barium platino cyanide solution. Properties of Gamma Rays• Gamma rays are electromagnetic in nature. • They are neutral rays. • Its velocity is equal to the velocity of light. • Ionization power is least. • Its penetration power is the greatest. • It effects the photographic plate. • It produces florescence with Barium Platino Cyanide. Nuclear FissionThe splitting of a nucleus into fragments with the emission of energy when bombarded by a neutron is called a fission process. Chain ReactionIn a fission reaction, each nucleus emits three neutrons. These neutrons collide with other uranium nuclei and cause fission in them emitting three more neutrons. These neutrons produce further fission in other nuclei and this process continues. This is called a Chain Reaction. Nuclear ReactorA system used to obtain a controlled amount of heat from nuclear fission is called a nuclear reactor. Working of a Nuclear ReactorThe fission material in a nuclear reactor is Uranium. This is called fuel element. The neutrons released from fission move with high velocities. The fast moving neutrons have to be slowed down before they cause further fission. The process of slowing down neutrons is called moderation. heavy water is used as a moderator. When a chain reaction starts, it may produce large number of neutrons, which may cause too much fission. The rate of chain reaction is controlled by inserting control rods which are commonly made of Boron.The heat produced is a nuclear reactor is carried away by the circulation of pressurized water or carbon dioxide gas inside the core of the reactor. This heat is used to produce steam. This steam can be used to run a power station for the generation of electricity. Nuclear FusionThe process in which two lighter nuclei are brought together to form another heavy nucleus is called the Fusion Reaction.When Deuterium and Tritium nuclei are brought together they form a Helium nucleus and release a large amount of energy and a neutron.

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