C.B.S.E. 2012 Sample Papers for X Science (5 Sets)

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of 16

I, 2012

SUMMATIVE ASSESSMENT I, 2012

/ SCIENCE

X / Class X

3 90

Time allowed : 3 hours Maximum Marks : 90

(i)

(ii)

(iii)

(iv)

(v) 1 3

(vi) 4 7 30

(vii) 8 19 50

(viii) 20 24 70

(ix) 25 42

General Instructions :

(i) The question paper comprises of two Sections, A and B. You are to attempt both the

sections.

(ii) All questions are compulsory.

(iii) There is no overall choice. However, internal choice has been provided in all the five

questions of five marks category. Only one option in such questions is to be attempted.

(iv) All questions of Section-A and all questions of Section-B are to be attempted separately.

(v) Question numbers 1 to 3 in Section-A are one mark questions. These are to be answered in

one word or in one sentence.

(vi) Question numbers 4 to 7 in Sections-A are two marks questions. These are to be answered

in about 30 words each.

(vii) Question numbers 8 to 19 in Section-A are three marks questions. These are to be answered


(viii) Question numbers 20 to 24 in Section-A are five marks questions. These are to be answered


(ix) Question numbers 25 to 42 in Section-B are multiple choice questions based on practical

skills. Each question is a one mark question. You are to select one most appropriate

response out of the four provided to you.

SC2-015

of 16

/ SECTION - A

1.

Mention the angle between a current carrying conductor and magnetic field for which the force experienced by this current carrying conductor placed in magnetic field is largest ?

1

2.

Name the sensory receptors found in the nose and on the tongue ?

1

3.

Define a solar panel.

1

4.

III

Write the balanced chemical equation for the following reaction and identify the type of reaction and define it. Iron III oxide reacts with Aluminium and gives molten iron and aluminium oxide.

2

5.

(a)

(b)

(c)

(d)

Name the following : (a) A metal which is preserved in kerosene (b) A lustrous coloured non metal (c) A metal which can melt while kept on palm. (d) A metal, which is a poor conductor of heat.

2

6. 800 W 6 30 ` 3.00

An electric heater rated 800 W operates 6 h/day. Find the cost of energy to operate it for 30 days at ` 3.00 per unit.

2

7.

Draw magnetic field lines produced around a current carrying straight conductor passing through cardboard. How will the strength of the magnetic field change, when the point where magnetic field is to be determined, is moved away from the straight wire carrying constant current ? Justify your answer.

2

of 16

8.

(i)

(ii)

A reddish brown coloured metal, used in electrical wires, when powdered and heated strongly in an open china dish, its colour turns black. When hydrogen gas is passed over this black substance, it regains its original colour. Based on the above information answer the following questions. (i) Name the metal and the black coloured substance formed. (ii) Write balanced chemical equations for both the reactions.

3

9. (a)

(b)

H2 SCl2 2 HClS

(c)

(a) Give an example for a combination reaction which is exothermic. (b) Identify the oxidising agent, reducing agent in the following reaction.

H2 SCl2 2 HClS

(c) Name the phenomenon due to which the taste and smell of oily food changes when kept for a long time in open. Suggest one method to prevent it.

3

10. (a)

(b) pH

(c)

(a) Write the name given to bases that are highly soluble in water ? Give an example. (b) How is tooth decay related to pH ? How can it be prevented ? (c) Why does bee sting cause pain and irritation ? Rubbing of baking soda on the sting area gives relief. How ?

3

11. (a)

(b)

(c)

(a) Why is calcium starts floating when added to water ? (b) Most of the metals do not give hydrogen while reacting with nitric acid. Why ? (c) Write equation for the reaction of iron with steam. Name the compound of iron obtained.

3

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12. (a) l r 10

(i)

(ii)

(b)

(a) Nichrome wire of length l and radius r has resistance of 10 . How would the resistance of the wire change when : (i) Only length of the wire is doubled ? (ii) Only diameter of the wire is doubled ? Justify your answer. (b) Why element of electrical heating devices are made up of alloys ?

3

13. 5 , 10 15 30V

10

Three resistors of 5 , 10 and 15 are connected in series and the combination is connected to battery of 30V. Ammeter and voltmeter are connected in the circuit. Draw a circuit diagram to connect all the devices in proper correct order. What is the current flowing and potential difference across 10 resistance ?

3

14.

What is meant by overloading of an electrical circuit ? Explain two possible causes due to which overloading may occur in household circuit ? Explain one precaution that should be taken to avoid the overloading of domestic electric circuit.

3

15. (a)

(b)

(a) Explain with the help of diagram, how amoeba takes its nutrition. (b) Assume that you are a veterinary surgeon and you had removed a good length of the small intestine of a bear that was suffering from a intestinal tumor. Now, would you suggest a plant based or an meat based diet for the bear after its recovery ? Give reason for your answer.

3

16. (a)

(i) (ii)

(b)

(a) Name the part of brain which controls (i) voluntary action, (ii) involuntary action. (b) What is the significance of the peripheral nervous system ? Name the components of this nervous system and distinguish between the origin

3

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of the two.

17.

Describe an activity to illustrate the phenomenon of phototropism and explain why does this occur.

3

18.

Draw schematic labeled diagram of box type solar cooker. Name two components of solar cooker which are responsible to increase the temperature inside the solar cooker. Explain their function.

3

19.

Explain geothermal energy. How can it be harnessed to produce electrical energy ?

3

20. (a) A B A B

(i) A B

(ii) A B

(b) Mg Cl2

Mg 12 Cl 17

(c)

(d)

(a) In the formation of compound between two atoms A and B, A loses two electrons and B gains one electron. (i) What is the nature of bond between A and B ? (ii) Suggest the formula of the compound formed between A and B. (b) On similar lines explain the formation of Mg Cl2 molecule.

(c) Common salt conducts electricity only in the molten state. Why ? (d) Why is melting point of NaCl high ?

/ OR

(a) MgO Mg

(b)

(c)

(a) Carbon cannot be used as reducing agent to obtain Mg from MgO. Why ? (b) How is sodium obtained from molten sodium chloride ? Give equation of the reactions. (c) How is copper obtained from its sulphide ore ? Give equations of the

5

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reactions.

21. (a)

(b)

(c)

(a) Identify the acid and the base whose combination forms the common salt that you use in your food. Write its formula and chemical name of this salt. Name the source from where it is obtained. (b) What is rock salt ? Mention its colour and the reason due to which it has this colour. (c) What happens when electricity is passed through brine ? Write the chemical equation for it.

/ OR

(a)

(b)

(c)

(a) Write the chemical name and chemical formula of washing soda. (b) How is it obtained from sodium chloride ? Give equations of the reactions. (c) Why it is called a basic salt ? Give its any one use.

5

22. (a)

(b) 220 V 5 A 176

(c)

(a) Calculate the resistance of the wire using the graph.

5

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(b) How many 176 resistors in parallel are required to carry 5A on a 220 V line ? (c) Define electric power. Derive relation between power, potential difference and resistance.

/ OR

(a) R1, R2, R3

(b)

(c) 5 A

(a) Three resistors R1, R2 and R3 are connected in parallel and the

combination is connected to battery, ammeter, voltmeter and key. Draw suitable circuit diagram. Obtain an expression for the effective resistance of the combination of resistors in parallel. (b) Why are electric bulbs filled with chemically inactive nitrogen or argon ? (c) What is meant by the statement that the rating of a fuse in a circuit is 5 A ?

23. (a)

(b) P S P

S

(i) P

(ii) P

(iii) P

(a) Define electromagnetic induction ? (b) Two coils P and S are wound over the same iron core. Coil P is connected to battery and key and the coil S is connected to galvanometer. Draw a suitable diagram of this arrangement and write your observations when : (i) Current in the coil P is started by closing the key. (ii) Current continues to flow in coil P. (iii) Current in coil P is stopped by removing the key. Explain the reason for such observations.

5

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/ OR

(a)

(b)

(c)

(a) Draw magnetic field lines around bar magnet. (b) Explain any two properties of magnetic field lines. (c) A current through a horizontal power line flows in east to west direction. What is the direction of magnetic field at a point directly below it ? State the rule which is used to find the direction of magnetic field in this case.

24.

(a)

(b)

(c)

Draw the diagram of sectional view of human heart and on it name and label the following parts : (a) The chamber of the heart that pumps out de-oxygenated blood. (b) The blood vessel that carries away oxygenated blood from the heart. (c) The blood vessel that receives de-oxygenated blood from the lower part of our body.

/ OR

(a)

(b)

(a) Draw the human respiratory system and label the following lung, bronchi, alveolar. (b) During breathing cycle what is the advantage of residual volume of air in lungs ? Explain.

5

/ SECTION - B

25.

(a) (b) (c) (d)

When ferrous sulphate crystals are heated, the colour of the residue formed is : (a) red (b) brown (c) orange (d) green

1

26.

(a)

(b)

(c)

1

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(d)

A small amount of quick lime is taken in a beaker. Water is added slowly to the beaker. Which of the following observations were noted ? (a) Hissing sound and the solution becomes hot (b) No characteristic sound and solution turns cold (c) Hissing sound and the solution becomes cold. (d) No characteristic sound and the solution becomes hot.

27. pH

(a) NaOH (b)

(c) HCl (d) NaHCO3

The colour of pH strip turned red when it was dipped in a sample. The sample could be : (a) dilute NaOH solution (b) tap water (c) dilute HCl solution (d) dilute NaHCO3 solution

1

28. pH

(a) pH

(b) pH

(c) pH

(d) pH

The correct method of finding pH of solution is to : (a) heat the solution in the test tube and expose the pH paper to the vapours formed. (b) pour solution from the test tube on pH paper (c) drop the pH paper into the solution (d) add a drop of solution on the pH paper using a dropper.

1

29. I II 10 mL HCl 10 mL NaOH

(a)

(b) I II

(c) II I

(d)

10 mL of HCl and 10 mL of NaOH solutions are taken in two separate beakers labelled I and II respectively. On adding Zinc granules to both, it is observed that at room temperature (a) Gas is evolved vigorously in both (b) Gas is evolved vigorously in beaker I and not in the beaker II (c) Gas is evolved vigorously in beaker II but not in the beaker I (d) No gas is evolved in either of the two beakers

1

30. 15

(a) (b)

(c) (d)

1

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A new iron nail is placed in a beaker containing aqueous copper sulphate solution. When the nail is taken out after 15 minutes, its surface is coated with (a) reddish deposit (b) greenish deposit (c) black deposit (d) white deposit

31.

(a) (b)

(c) (d)

A piece of granulated Zn was dropped into copper sulphate solution. After some time the colour of solution changed from (a) light green to blue (b) blue to colourless (c) light green to colourless (d) blue to green

1

32. 2A 10 5 V 20

8

8

(a) 1.25 (b) 2 (c) 0.75 (d) 1.5 The number of division in ammeter of range 2A is 10 and voltmeter of range 5 V is 20. When the switch of the circuit given below is closed, ammeter reading is at 8th division and voltmeter reading is at 8th divisions. The value of resistance of resistor is

(a) 1.25 (b) 2 (c) 0.75 (d) 1.5

1

33. /

(a) (b)

(c) (d)

1

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In Ohms law experiment, the physical quantity/quantities which is/are to kept constant while doing experiment is/are : (a) potential difference (b) current (c) temperature (d) potential difference, current, temperature

34. R1, R2 R1>R2

A, B, C

(a) R1, R2,

(b) R2, R1

(c) R2, R1,

(d) R1, R2Ohms law experiment is performed separately with individual resistors R1, R2

[R1>R2] and series combination of R1, R2. Graph is plotted between potential

difference (V) and current (I) as shown in figure for each case : Identify which one is for R1, R2 and combination of resistors ?

In the graph A, B and C respectively represents

(a) R1, R2 and series combination

(b) series combination, R2, R1

(c) R2, R1 and series combination

(d) series combination, R1, R2

1

35.

/ /

(a) I, II (b) II, III (c) II (d) I

1

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Three students drew following circuit diagrams to find resistance of parallel combination of two resistors. Correct circuit diagram/diagrams are

(a) I, II (b) II, III (c) II only (d) I only

36.

The circuit diagram shown below is used to find the effective resistance of two resistors in series. Which circuit diagram represents correctly ?

1

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37.

(a)

(b)

(c)

(d)

Other than light, which of the following are also essential for photosynthesis ? (a) carbon di-oxide, water, minerals, chlorophyll (b) carbon di-oxide, water, vitamins, chlorophyll (c) carbon, water, minerals, chlorophyll (d) carbon di-oxide, water, hormones, chlorophyll

1

38. 1

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(a) A (b) B (c) C (d) DWhich of the following set-up will give a positive result for starch test after boiling the leaf in alcohol ?

(a) A (b) B (c) C (d) D

39.

(a) (b) (c) (d)

The stomatal opening is controlled by guard cells. If the stomatal opening is to remain open how should the guard cells be ? (a) stretched (b) swollen (c) rigid (d) shrunk

1

40.

(a)

(b)

(c)

(d)

The guard cells are also capable of photosynthesis because they have : (a) cytoplasm, nucleus, centrioles (b) cytoplasm, nucleus, centrosome (c) cytoplasm, nucleus, chromosomes (d) cytoplasm, nucleus, chloroplasts

1

41.

(a)

(b)

(c)

1

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(d)

The gas released from germinating seeds indicate that the seeds are : (a) alive and decaying (b) alive and respiring (c) dead and decaying (d) alive and decomposing

42.

(a) CO2

(b) CO2

(c) CO2

(d) CO2 In the experimental set-up shown in the figure, water is found to rise in the delivery tube because :

(a) sodium hydroxide kept in the small test tube absorbs CO2

(b) calcium hydroxide kept in the small test tube absorbs CO2

(c) chromium hydroxide kept in the small test tube absorbs CO2

(d) potassium hydroxide in the small test tube absorbs CO2

1

- o O o -

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School Principal




any circumstances.



regard.







of 13

I, 2012


/ SCIENCE

X / Class X

3 90


(i)

(ii)

(iii)

(iv)

(v) 1 3

(vi) 4 7 30

(vii) 8 19 50

(viii) 20 24 70

(ix) 25 42



sections.
















SC2-018

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SECTION-A

1.

Give two characteristics of magnetic field lines.

1

2.

Name the part of the brain which controls posture and balance of the body ?

1

3.

Mention two different ways of harnessing energy from ocean.

1

4.

Identify the type of chemical reaction and also write the chemical equation for the

reaction that takes place when a solution of potassium chloride is mixed with silver

nitrate solution. Write the chemical name of one of the products obtained.

2

5.

Why do ionic compounds have high melting points ? State reason.

2

6. 1200 220 V

100

How much current will an electric bulb draw from 220 V source if the resistance of the

bulb is 1200 ? If in place of bulb, a heater of resistance 100 is connected to the

sources calculate the current drawn by it.

2

7. PQ A B

r1 r

2 r

1 > r

2

PQ is a current carrying conductor producing magnetic field around it. A and B are

two points at a distance r1 and r

2 from it. If r

1 > r

2, where is the magnetic strength

greater and why ?

2

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8.

(a)

(b)

(c)

The following diagram displays a chemical reaction. Observe carefully and answer

the following questions :

(a) Identify the type of chemical reaction that will take place and define it.

How will the colour of the salt change ?

(b) Write the chemical equation of the reaction that takes place.

(c) Mention one commercial use of this salt.

3

9.

What is rancidity ? Mention any two ways by which rancidity can be

prevented ?

3

10.

Differentiate between strong and weak acids. Identify the strong and weak acids from

the following list of acids.

Hydrochloric acid, acetic acid, formic acid, nitric acid.

3

11. (a) CaO

20 8

(b)

(a) Explain the formation of ionic compound CaO with electron dot structure.

Atomic number of calcium and oxygen are 20 and 8 respectively.

(b) Name the constituent metals of bronze.

3

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12. 6

(i) 9 (ii) 4

How you would connect three resistors each of resistance 6 so that the combination has a resistance of (i) 9 (ii) 4 ? Justify your answer.

3

13. (a) R V I

(b) 200 V 0.5 A

(a) Define electric power. A device of resistance R is connected across a source of V voltage and draws a current I. Derive an expression for power in terms of voltage and resistance.

(b) An electric bulb is connected to a 200 V generator. The current is 0.5 A. What is the power of the bulb ?

3

14.

Define a solenoid. With the help of a suitable diagram show the pattern of magnetic field lines around a current carrying solenoid. State the region where field is uniform.

3

15.

List the events that occur during the process of photosynthesis.

3

16. (a)

(b)

(a) State the function of plant hormones. Name a plant hormone which is essential for cell division ?

(b) Name the hormone which is involved in phototropism. Explain its role.

3

17. (a)

(i) (ii)

(b)

(a) Identify the glands that secrete (i) insulin (ii) thyroxin (b) Explain with an example how the timing and amount of hormone secreted are

regulated in human body.

3

18.

Explain three disadvantages of burning fossil fuels.

3

19.

List three characteristics of a good source of energy and mention any three qualities of a good fuel.

3

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20. (a)

(b)

(c)

(i)

(ii)

(a) Write the chemical name of the coating that forms on silver and copper articles when these are left exposed to moist air.

(b) Explain what is galvanisation. What purpose is served by it ? (c) Define an alloy. How are alloys prepared ? How do the properties of iron

change when : (i) small quantity of carbon, (ii) nickel and chromium are mixed with it.

OR

(a)

(b)

(a) Differentiate between roasting and calcination. Explain the two with the help of suitable chemical equations. How is zinc extracted from its ore.

(b) Name two metals that can be used to reduce metal oxides to metals.

5

21.

Describe an activity with diagram to illustrate that the reaction of metal carbonates and metal bicarbonates with acids produces carbon dioxide. Write the relevant equations of all the reactions that take place. Name any two forms in which calcium carbonate is found in nature.

OR

(a) CaOCl2

(b)

(a) Write the common name of CaOCl2. How is it prepared ? Write the chemical equation of the reaction involved in the process. Give any two uses of it.

(b) Write the chemical name of washing soda. How is it prepared ? Give the relevant chemical equations.

5

22. (a) 10

(i)

(ii) 6 V

(b)

5

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(a) Two identical resistors each of resistance 10 are connected in (i) series (ii) parallel to a 6 V battery. Calculate the ratio of power consumed in

the combination of resistors in two cases. (b) Draw the circuit diagram of the two cases.

OR

R110 ,R240 , R330 , R420 R1 R2 RA

R3, R4 RB

RA 12 V RB

RA RB

(a) RA RB

(b)

Given that R110 ,R240 , R330 , R420 and RA is the parallel combination of R1 and R2 whereas RB is the parallel combination of R3 and R4. Combination RA is connected to the positive terminal of 12 V battery while combination RB is connected to the negative terminal. Ammeter A is connected between the resistors RA and RB. (a) Find RA and RB. Also calculate total resistance in the circuit. (b) Draw the circuit diagram showing above combinations connected to battery

and ammeter.

23. (a)

(b)

(c)

(a) Explain two safety measures commonly used in electric circuits and appliances. (b) An electron enters a magnetic field at right angles to it as shown in figure.

What will be the direction of force acting on the electron. State the rule which gives direction of force on electron.

(c) If instead of electron, a neutron enters a field, what will be its direction of

motion ? Give reason for your answer.

OR

(a) 220 V 5 A 2 kW

(b)

5

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(a) An electric oven of 2 kW power rating is operated in a domestic electric circuit of 220 V that has a current rating of 5 A. What result do you expect ? Explain.

(b) Describe an activity with diagram to show that current is induced in a coil

when magnetic field around it is changed.

24. (a)

(i) (ii)

(iii) (iv)

(b)

(a) Draw a sectional view of the human heart and label on it, (i) Pulmonary artery (ii) Right auricle (iii) venacava (iv) pulmonary vein (b) Explain why ventricles have thick muscular walls than the atria ?

OR

(a)

(b)

(i)

(ii)

(iii)

(a) Define excretion. Name any two substances that are selectively reabsorbed. (b) Draw and label the following parts in the human excretory system. (i) Right Kidney (ii) Urinary Bladder (iii) Right renal artery

5

/ SECTION B

25. 30

(a) (b) (c) (d)

When iron nails are kept in copper sulphate solution for 30 minutes, the colour of solution changes into : (a) red (b) pink (c) orange (d) light green

1

26.

(a) (b) (c) (d)

The colour of the precipitate formed when barium chloride solution reacts with sodium sulphate solution is : (a) yellow (b) orange (c) green (d) white

1

27.

(a) (b)

(c) (d)

1

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A student adds a few drops of universal indicator to a solution and observes colour changes to orange. The solution would be : (a) strong acid (b) strong base (c) weak acid (d) weak base

28.

(a) I pH II III

(b) IV pH I II

(c) IV pH I, II III

(d) I pH III IV

Observe the following figures and choose the correct option.

(a) pH of I is greater than of II and III (b) pH of IV is less than of I and II (c) pH of IV is greater than of I, II and III (d) pH of I is less than of III of and IV

1

29.

(a)

(b)

(c)

(d)

When hydrochloric acid reacts with zinc : (a) surface of zinc becomes white. (b) surface of zinc becomes black and dull. (c) zinc becomes powder. (d) the reaction mixture turns red.

1

30. Cu, Fe, Zn Al

(a) Cu Zn (b) Al Cu

(c) Fe Al (d) Zn Al

1

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Freshly prepared iron sulphate solution was taken in each of four test tubes. Strips of Cu, Fe, Zn and Al were introduced in different test tubes, a black residue was observed in two test tubes. The pair of metals forming the residue is : (a) Cu and Zn (b) Al and Cu (c) Fe and Al (d) Zn and Al

31. I, II, III, IV

(a) I, II (b) II, III (c) III, IV (d) I, IV A student added a piece of zinc metal to four test tubes I, II, III, IV which respectively contain aqueous solution of aluminium sulphate, zinc sulphate, ferrous sulphate and copper sulphate. In which solution he observed that the reaction has taken place. (a) I, II (b) II, III (c) III, IV (d) I, IV

1

32. (I) (V)

The graph between current (I) and the potential difference in the experimental verification of Ohms law were drawn by four students as shown in fig. Which one of the following is correct ?

1

33.

(a)

(b)

(c)

(d)

1

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Which of the following is the correct method to connect the ammeter and voltmeter with resistance in the circuit to verify Ohms law ? (a) Ammeter and voltmeter in series (b) Ammeter in series and voltmeter in parallel (c) Ammeter in parallel and voltmeter in series (d) Ammeter and voltmeter in parallel.

34. (0 3) 30

(a) 1.0 A (b) 0.5 A (c) 0.1 A (d) 0.01 A An ammeter has a range of (0 3) ampere and there are 30 divisions on its scale. What is its least count ? (a) 1.0 A (b) 0.5 A (c) 0.1 A (d) 0.01 A

1

35. A1, A2, A3 I1, I2, I3

(a) I1< I2 (b) I3< I2 (c) I1 I2 I3 (d) I1 I3 The statement that is most correct about the readings of ammeters A1, A2 and A3 connected in the following circuit (currents read by each are shown by I1, I2, I3 respectively).

(a) I1< I2 (b) I3< I2 (c) I1 I2 I3 (d) I1 I3

1

36. 2

(a) 4 (b) 6 (c) 9 (d) 2 Equivalent resistance of three resistors each of resistance of 2 connected in series as determined experimentally should be : (a) 4 (b) 6 (c) 9 (d) 2

1

37.

(a) (b)

(c) (d)

A leaf is boiled in alcohol before using iodine for starch test in order to : (a) dissolve starch (b) dissolve chlorophyll (c) soften the leaf (d) to kill the enzymes

1

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38. X

(a) A (b) B (c) C (d) D A leaf from a destarched plant is covered with black paper strip as shown in the figure X and then starch test is made on the leaf. The results of Iodine test will be shown as

in the diagram :

(a) A (b) B (c) C (d) D

1

39. X Y

X Y

(a) (b) (c) (d)

Four students Sheela, Mala, Bina and Heena, made the records given below for the parts marked X and Y in the diagram.

1

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Student X Y

Sheela Stoma Nucleus

Mala Nucleus Stoma

Bina Epidermal cell Nucleus

Heena Stoma Epidermal cell

The correct record out of these is the one given by : (a) Sheela (b) Mala (c) Bina (d) Heena

40.

(a) (b)

(c) (d)

While preparing a temporary stained mount of a leaf epidermal peel the extra stain is removed by : (a) Washing with water (b) Washing with alcohol (c) Absorbing with filter paper (d) Absorbing with cotton

1

41. S

(a) (b)

(c) (d)

In the experimental set up shown in the figure, the chemical taken in the small test tube hanging inside the conical flask marked as S is :

(a) alcohol (b) water (c) potassium hydroxide (d) potassium iodide

1

42. CO2

(a) (b)

(c) (d)

To show that CO2 is released during respiration, we take : (a) dry seeds (b) boiled seeds (c) wet seeds (d) germinating seeds

1

- o O o -

of 17


School Principal




any circumstances.



regard.







of 17

I, 2012


/ SCIENCE

X / Class X

3 90


(i)

(ii)

(iii)

(iv)

(v) 1 3

(vi) 4 7 30

(vii) 8 19 50

(viii) 20 24 70

(ix) 25 42



sections.
















SC2-031

of 17

SECTION-A

1. (AC) (DC)

Mention the advantage of AC over DC for long distance transmission ?

1

2.

Give one example of chemotropism.

1

3.

Name an efficient fuel obtained from cow dung and other animal and plant wastes.

Also mention its main constituent.

1

4.

(i)

(ii)

Write balanced chemical equations for the following reactions :

(i) Silver bromide on exposure to sun light decomposes into silver and bromine

(ii) Sodium metal reacts with water to form sodium hydroxide and hydrogen gas.

2

5.

Write two observations that you will make when an iron nail is kept in an aqueous

solution of copper sulphate ? Write the chemical equation for this reaction.

2

6. 1.5V 5, 4, 3

Draw a schematic diagram of circuit consisting of a battery of 1.5V and three

resistances of 5, 4, 3 respectively joined in series with an ammeter and a key.

Find out the current in the circuit.

2

7.

(i)

(ii)

A current carrying conductor produces a magnetic field around it. Is there a similar

magnetic field produced around a thin beam of moving

(i) electrons

(ii) neutrons. Justify your answer.

2

8.

(a)

(b)

(c)

3

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A small amount of quick lime is added to water in a beaker. (a) Name and define the type of reaction that has taken place. (b) Write balanced chemical equation for the above reaction. Write the chemical

name of product obtained. (c) State two observations that you will make in the reaction.

9.

Write balanced chemical equation for the reactions that take place during respiration.

Identify the type of combination reaction that takes place during this process and

justify the name. Give one more example of this type of reaction.

3

10.

(i)

(ii)

(iii)

A compound which is prepared from gypsum, has the property of hardening when

mixed with right quantity of water.

(i) Identify the compound and write its chemical formula.

(ii) Write the chemical equation for its preparation.

(iii) List any two uses of the above compound.

3

11.

(i)

(ii)

(iii)

Give reasons for the following :

(i) Ionic compounds have high melting point and boiling point.

(ii) Ionic compounds conduct electricity in molten state.

(iii) Ionic compounds are solids at room temperature and are somewhat hard.

3

12.

A resistance wire is stretched to double its length so that its area of cross section is

halved. How will its resistance change ? Will any change be observed in its resistivity?

Justify your answer.

3

of 17

13.

(i)

(ii)

(iii)

For the circuit diagram given below :

Calculate : (i) Value of current flowing through each resistor, (ii) The total current in the circuit, (iii) The total effective resistance of the circuit.

3

14. 2000 W, 220V

5A

Explain the function of fuse in a domestic electric circuit ? An electric oven having power rating 2000 W, 220V is used in an electric circuit, having a fuse of 5A rating. What is likely to happen when the oven is switched on ? Explain.

3

15.

In human alimentary canal name the site of complete digestion of various components of food. Explain the process of digestion.

3

16.

Name the property that causes tendril to circle around the object ? Explain how it happens and how is plant benefitted by it ?

3

17.

(i)

(ii)

(iii)

3

of 17

Smitas father has been advised by a doctor to reduce his sugar intake. (i) Name the disease he is suffering from and name the hormone whose deficiency

causes it. (ii) Identify the gland that secretes it and mention the function of this hormone. (iii) Explain how the time and amount of secretion of this hormone is regulated in

human system.

18.

Distinguish between renewable and non-renewable sources of energy. Also give an

example of each of these sources.

3

19. (i)

(ii)

(i) Why are solar heating devices painted black ?

(ii) Name two such devices and state two limitations of these.

3

20. (i)

(ii)

(i) Explain the steps for extraction of copper from its sulphide ore. Write the

balanced equations involved in the process.

(ii) What is meant by refining of metals ? Draw a diagram of electrolytic refining of

copper and name the substances used as cathode, anode and the electrolyte.

OR

How is the method of extraction of metals high up in the reactivity series different from

that for metals in the middle ? Why the same process cannot be applied for them ?

Explain giving equations, the extraction of sodium.

5

21. (i)

(ii)

(a) (b)

(iii)

pH pH

5

of 17

(i) Name the gas which is liberated when an acid reacts with a metal ? How will

you test the presence of this gas ?

(ii) Write the chemical equation for the reaction of zinc metal with

(a) hydrochloric acid and (b) with sodium hydroxide. Write the chemical name

of salt obtained in each case.

(iii) Identify the acid and base for ammonium chloride salt. What would be the

nature of this salt ? Mention the pH range of this salt.

OR

(i)

(ii)

(iii) A, B, C D pH 6, 9, 12, 7

(a)

(b) H

(c) pH C D

(i) Explain why is hydrochloric acid a strong acid and acetic acid, a weak acid ?

How can it be verified ?

(ii) Explain why aqueous solution of an acid conducts electricity.

(iii) You have four solutions A, B, C and D. The pH of solution A is 6, B is 9, C is 12

and D is 7,

(a) Identify the most acidic and most basic solutions.

(b) Arrange the above four solutions in the increasing order of H ion

concentration.

(c) State the change in colour of pH paper on dipping in solution C and D.

22. (i) SI

(ii) XY, 1.5V

(a) X Y XY

(b) V I A C V I

5

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(i) State the SI unit of current and define it.

(ii) An electric circuit consisting of a nichrome wire XY an ammeter, a voltmeter,

four cells of 1.5V each and a plug key is to be set up.

(a) for studying the relationship between the potential difference maintained between the point X and Y and the current flowing through the wire XY. Draw its circuit. (b) Graph shown in figure was plotted between V and I. What would be

the value of V and I corresponding to points A and C on graph. Analyse these values and draw conclusion.

OR

P

(i)

(ii)

(iii)

Three bulbs each having power P are connected in series in an electric circuit. In another circuit another set of three bulbs of same power are connected in parallel to the same source. (i) Will the bulbs in both the circuits glow with the same brightness? Justify your

answer. (ii) Now let one bulb in each circuit get fused. Will the rest of the bulbs continue to

glow in each circuit ? Give reason. (iii) Representing each bulb by a resistor, draw circuit diagram for each case.

23. (i)

(ii)

(iii)

(i) Define solenoid ?

(ii) Sketch the pattern of magnetic field around a current carrying solenoid.

(iii) How can you determine the north and south poles of a current carrying

solenoid with the help of a bar magnet ? Explain.

OR

5

of 17

I

(i)

(a) K

(b) K

(ii)

(iii)

(iv)

(v)

Two coils of insulated copper wire are wound over a non conducting cylinder as

shown. Coil I has larger number of turns.

(i) Write your observations when,

(a) key K is closed;

(b) key K is opened;

(ii) Give reason for your observations.

(iii) Mention the name of the phenomenon involved and define it.

(iv) Name the two coils used in this experiment.

(v) State the rule which gives the direction of induced current.

24. (i)

(a)

(b)

(c)

(d)

(i) Draw a neat diagram of cross section of human heart. Name and label the

following on the diagram.

(a) Structure / part that divides heart into right and left halves and

prevents mixing of oxygenated and deoxygenated blood.

5

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(b) Part which prevents the backward flow of blood.

(c) Chamber that receives deoxygenated blood from various parts of the

body.

(d) Chamber from where oxygenated blood is pumped out to various parts of the body.

OR

(i)

(a) (b)

(c) (d)

(ii)

(a)

(b)

(i) Draw a neat diagram of human respiratory system and label the following parts

on it :

(a) trachea (b) bronchi

(c) alveoli (d) diaphragm

(ii) Give reason :

(a) Rings of cartilage are present in trachea.

(b) Lungs always contain a residual volume of air.

/ SECTION - B

25.

(a) (b)

(c) (d)

Aluminum strip was placed in a solution of copper sulphate. After one hour, it was

observed that the colour of solution changes. The colour of solution would become.

(a) light green (b) colourless

(c) dark brown (d) deep blue

1

26.

(a) I (b) II (c) III (d) IV

1

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On mixing aqueous solutions of sodium sulphate and barium chloride, the correct observation is shown in test tube.


27. pH A B pH A

B A B

(a) HCl (b) HCl

(c) HCl (d) HCl

A student dipped strip of pH paper in solutions taken in beakers A and B. The

colour of strip changed to red in breaker A and green in breaker B. The samples in

A and B respectively are : (a) HCl, water (b) HCl, lemon juice (c) lemon juice, HCl (d) water, HCl

1

28. X NaOH pH X

Y

(a) (b) (c) (d)

Bottle X contains NaOH solution and bottle Y contains distilled water. On dipping pH paper strips in each of the solutions, the colour seen in X and Y respectively are : (a) blue, red (b) blue, green (c) green, blue (d) red, blue

1

29. HCl

(a) (b)

(c) (d)

Which one of the following substances will be required to identify the gas evolved, when dil. HCl reacts with solid sodium carbonate. (a) red litmus solution (b) lime water (c) blue litmus solution (d) zinc granules

1

30. I, II, III IV 10 mL

(a) I, III (b) I, IV (c) II, IV (d) III, IV

1

of 17

10 mL of freshly prepared iron sulphate solution was taken in each of four test tubes I,

II, III and IV. Strips of copper, iron, zinc and aluminium were respectively introduced

in the test tubes I, II, III, and IV. A black residue was obtained in two of them. These

test tubes are :

(a) I, III (b) I, IV (c) II, IV (d) III, IV

31. CuSO4 30

(a) (b)

(c) (d)

Zn granules were added to a solution of CuSO4. After 30 minutes, it was observed that

the blue colour of solution changes and a layer gets deposited on Zn granules. The

colour of the solution and that of the coating would respectively be :

(a) green, black (b) colourless, black

(c) colourless, reddish brown (d) green, reddish brown.

1

32.

(a) 130 mA, 0.8V (b) 160mA, 0.8V

(c) 160mA, 0.6V (d) 130mA, 0.6V

The reading shown by milliammeter and voltmeter are :

(a) 130 mA, 0.8V (b) 160mA, 0.8V (c) 160mA, 0.6V (d) 130mA, 0.6V

1

of 17

33. 1.5V 6V


A student has to connect 4 cells of 1.5V each to form a battery of 6V. He connects the

cells in four different ways as shown.

The correct arrangement is.


1

34. I V V I

(a) I (b) II (c) III (d) IV Four students plot graphs between V and I, showing dependence of current I on potential difference, V across a resistor, as shown

The correct graph is (a) I (b) II (c) III (d) IV

1

35. 20 V 0.6 A

(a) 1.2 (b) 3.3 (c) 3.0 (d) 15

1

of 17

In the circuit given below, on plugging the key, the voltmeter reads 2.0 V but ammeter reads 0.6 A. The resistance of the combination is

(a) 1.2 (b) 3.3 (c) 3.0 (d) 15

36.

(a) I (b) II (c) III (d) IV In an experiment to find the equivalent resistance of two resistors connected in series, four circuits were set up as shown.

The voltmeter has been correctly connected in the arrangement (a) I (b) II (c) III (d) IV

1

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37.

A

B

C

D

(a) B C

(b) B C

(c) A B

(d) B D

A student covered the surfaces of four leaves of a destarched potted plants as follows :

and then kept for some time under sun light

Leaf A with colourless transparent paper.

Leaf B with black opaque paper.

Leaf C with white opaque paper.

Leaf D with light yellow transparent paper.

On testing for starch, the correct observation will be :

(a) Covered portions of leaf B and C change to blue black.

(b) Covered portions of leaf B and C change to white.

(c) Covered portion of leaf A and B change to blue black.

(d) Covered portion of leaf B and D change to blue black

1

38.

(a)

(b)

(c)

(d)

While performing the experiment to show that light is necessary for photosynthesis, a student boils the leaf in alcohol before using iodine for starch - test. He does it to (a) make the leaf soft. (b) make the leaf cells dead. (c) remove chlorophyll from the leaf. (d) make the leaf react with iodine.

1

39.

(a)

(b)

(c)

(d)

1

of 17

While preparing a temporary stained mount of a leaf peel, the extra stain from the slide is removed by (a) washing with water. (b) using a dropper. (c) soaking with filter paper. (d) absorbing with cotton.

40.

(a) A (b) B (c) C (d) D Four students observed the stomata in leaf peel under the microscope and draw the following diagrams.

The correct diagram is (a) A (b) B (c) C (d) D

1

41. CO2

(a)

(b) CO2

(c)

(d) CO2 KOH

1

of 17

The experimental setup shown below shows that CO2 is released during respiration.

Water rises in the delivery tube because _____ (a) Oxygen of the flask is used by the germinating seeds. (b) CO2 given out by germinating seeds enters into the delivery tube. (c) Moisture in the germinating seeds enters into the delivery tube. (d) CO2 given out by the germinating seeds is absorbed by KOH.

42. CO2

KOH

(a)

(b)

(c)

(d)

In the experimental set up to show that CO2 is given out during respiration, KOH is kept in the small test tube inside the flask. (a) makes the air inside the flask alkaline. (b) absorbs moisture present in the flask. (c) creates partial vacuum in the flask. (d) provides oxygen for respiration to the germinating seeds.

1

- o 0 o -

of 17


School Principal




any circumstances.



regard.







of 17

I, 2012


/ SCIENCE

X / Class X

3 90


(i)

(ii)

(iii)

(iv)

(v) 1 3

(vi) 4 7 30

(vii) 8 19 50

(viii) 20 24 70

(ix) 25 42



sections.
















SC2-036

of 17

SECTION-A

1. A.C D.C

List any one point of difference between AC and DC.

1

2.

Mention the part of the body where gustatory and of olfactory receptors are located.

1

3.

Name the two major components present in the left-over slurry of a bio gas plant.

1

4.

(i)

(ii)

Write the skeletal equation for the following reactions : (i) Hydrogen sulphide reacts with sulphur dioxide to form sulphur and

water. (ii) Methane on burning combines with oxygen to produce carbon dioxide

and water.

2

5.

(i)

(ii)

Give reason for the following : (i) Metals are good conductors of electricity whereas non-metals are not. (ii) Ionic compounds have usually high melting and boiling points.

2

6.

SI

State the factors on which at a given temperature the resistance of a cylindrical conductor depends. State the SI unit of resistivity.

2

7.

Explain the terms : overloading and short-circuiting.

2

8.

(i) 2 PbO C Pb CO2

(ii) MnO2 4HCl MnCl2 2H2O Cl2

What is redox reaction ? Identify the substance oxidised and the substance reduced in the following reactions :

(i) 2 Pb O C Pb CO2

(ii) MnO2 4HCl MnCl2 2H2O Cl2

3

of 17

9.

The smell and taste of food containing fats and oils changes after sometime. Why does this happen ? Name the process. List two ways which help to slow down the above mentioned process.

3

10.

Write the chemical formula of bleaching powder ? Write balanced chemical

equation involved in the preparation of bleaching powder and write its three

uses.

3

11.

Define (i) mineral, (ii) ore. Aluminium occurs in combined state whereas gold is found in free state in nature. Why ?

3

12.

(i)

(ii)

(iii)

Explain the following : (i) The elements of electric heating devices such as bread-toasters and

electric iron are made of an alloy rather than of a pure metal. (ii) Series arrangement is not used for domestic circuits. (iii) Copper and aluminium wires are usually employed for electricity

transmission.

3

13.

3

of 17

Find out the reading of ammeter and voltmeter in the circuit given below :

14.

With the help of a diagram, describe an activity to draw the magnetic field lines around a coil carrying current.

3

15.

List the three kinds of blood vessels of human circulatory system and write their functions in tabular form.

3

16. (a)

(b)

(a) How is brain protected from injury and shock ? (b) Name two main parts of hind brain and state the function of each.

3

17.

Explain how the human body responds when adrenaline is secreted into the blood.

3

18. (i)

(ii)

(i) Draw a schematic diagram of a bio-gas plant. (ii) Write any two advantages of obtaining biogas from animal dung and

bio-wastes.

3

19. (i)

(a)

(b)

(ii)

(i) Name the device used to convert : (a) Solar energy into heat (b) Solar energy into electricity (ii) Mention two limitations of solar energy.

3

20. (a) 5

of 17

(b)

(i)

(ii)

(iii)

(a) List two differences between calcination and roasting in tabular form. (b) Which method will you use to reduce the following ? Explain by giving a

suitable example. (i) oxides of less reactive metals (ii) oxides of moderately reactive metals (iii) oxides of highly reactive metals

/OR

Write the names and symbols of two most reactive metals. Explain by drawing electronic structure how any one of the two metals react with a halogen. State any four physical properties of the compound formed.

21. (i) 'X'

X

X HCl

(ii)

(i) Dry pellets of a base 'X' when kept in open absorbs moisture and turns sticky. The compound is also formed by chlor-alkali process. Write chemical name and formula of X. Describe chlor-alkali process with balanced chemical equation. Name the type of reaction occurs when X is treated with dilute hydrochloric acid. Write the chemical equation.

(ii) While diluting an acid, why is it recommended that the acid should be added to water and not water to the acid ?

/OR

(a)

(b) pH

(c)

(a) Bee sting leaves a chemical substance that causes pain and irritation. Name the chemical substance. Identify the type of substance which may give relief on the stung area when applied on it.

(b) Mention the pH value below which tooth decay begins. How this fall below this value ? Explain the ill effect of the acidic medium in the

5

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mouth. How can this be prevented ? (c) What are strong acids and weak acids ? Give an example of each.

22. (i) 1

(ii) 12 (i) (ii)

6 V

(iii)

(i) What is meant by the statement that the resistance of a wire is 1 ?

(ii) Two identical resistors each of resistance 12 are connected (i) in series

(ii) in parallel, inturn to a battery of 6 V.

Calculate the ratio of power consumed in the combination of resistors in

the two cases.

(iii) What combination is used for connecting in the circuit to measure the

potential difference across two points ?

/OR

(i) R1, R2 R3

(ii) 3A, 5A 10A 220 V

1 kW

(i) Derive an expression for the equivalent resistance of three resistors R1,

R2 and R3 connected in series.

(ii) Fuse of 3A, 5A and 10A are available. Calculate and select the fuse for

operating electric iron of 1 kW power at 220 V line.

5

23. (i)

(ii)

(a)

(b)

(c)

(iii)

(i) State Flemings left hand rule. (ii) A coil of insulated copper wire is connected to a galvanometer. What

happens if a bar magnet is : (a) pushed into the coil (b) withdrawn from inside the coil (c) held stationary inside the coil Give reasons for your observation. (iii) Mention one more method of inducing current in a coil.

5

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/OR

(i)

(a)

(b)

(ii)

(iii)

(i) How will the magnetic field around a current carrying straight conductor be affected on :

(a) increasing the current through the conductor ? (b) changing the direction of flow of current in the conductor ? (ii) Describe an activity with diagram to draw magnetic field lines due to a

current carrying circular loop. (iii) State the rule used to find the direction of magnetic field due to a current

carrying circular loop. 24. (a)

(i)

(ii)

(iii)

(iv)

(b)

(a) Draw a diagram of human respiratory system and label the following : (i) part where air is filtered by fine hair and mucus (ii) part which terminates in balloon like structures (iii) balloon like structures where exchange of gases takes place. (iv) part which separates chest cavity from abdominal cavity. (b) Why is the rate of breathing in aquatic organisms much faster than in

terrestrial organisms ?

/OR

(a)

(i)

(ii)

(iii)

(iv)

(b)

(a) Draw a diagram of human excretory system and label the following : (i) part in which urine is produced (ii) part which stores the urine (iii) part which connects (i) and (ii) (iv) part from which urine is passed out. (b) Name the factors on which the amount of water reabsorbed along the

tubular part of nephron depend on ?

5

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/ SECTION - B

25. Al, Zn, Cu Fe Zn SO4, CuSO4, Al2 (SO4)3 FeSO4

Metal Zn SO4 Cu SO4 Al2 (SO4)3 Fe SO4

Zn Cu

Al Fe

(a) Zn > Fe > Al > Cu (b) Al > Fe > Zn > Cu (c) Zn > Al > Fe > Cu (d) Al > Zn > Fe > Cu In an experiment each of the metals Al, Zn, Cu and Fe are reacted with ZnSO4,

CuSO4, Al2 (SO4)3 and FeSO4, solutions. The results are tabulated as follows

where means that the reaction occurs and means no reaction occurs.

Metal Zn SO4 Cu SO4 Al2 (SO4)3 Fe SO4

Zn Cu

Al Fe

On the basis of the above result the order of the reactivity of the metals may be concluded as : (a) Zn > Fe > Al > Cu (b) Al > Fe > Zn > Cu (c) Zn > Al > Fe > Cu (d) Al > Zn > Fe > Cu

1

26. 10

(a) Al2 (SO4)3 (b) Cu SO4

(c) Fe SO4 (d) Zn SO4

Some iron nails were dropped in an unknown solution taken in a beaker and left

for 10 minutes. It was then observed that a brown coating is formed on nails.

The solution is of :

(a) Al2 (SO4)3 (b) Cu SO4

(c) Fe SO4 (d) ZnSO4

1

27. A B pH

A B

(a) (b)

(c) (d)

Bottle A contains acetic acid and bottle B contains sodium carbonate solution. When pH paper is dipped in each of the solution, the colour seen in A and B respectively will be : (a) blue, orange (b) orange, green (c) orange, blue (d) green, blue

1

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28. X,Y,Z

X Y Z

pH

(a) X, Y, Z (b) Z, X, Y (c) Y, X, Z (d) Z, Y, X

On adding a few drops of universal indicator to three unknown colourless

solutions (X), (Y) and (Z) taken separately in three test tubes shown in the

following diagrams, a student observed the changes in colour as green in (X), red

in (Y) and violet in (Z).

Arrangement of solution in the decreasing order of pH is :

(a) X, Y, Z (b) Z, X, Y (c) Y, X, Z (d) Z, Y, X

1

29. 10 mL HCl 10 mL NaOH I II

(a) II I

(b)

(c)

(d) I II

10 mL of HCl and 10 mL of NaOH solutions are contained in two separate beakers labeled I and II respectively. On adding zinc granules to both, it is observed that at room temperature : (a) gas is evolved in beaker II but not in beaker I (b) no gas is evolved in either of the two beakers (c) gas is evolved vigorously in both (d) gas is evolved vigorously in beaker I but not so in beaker II.

1

30. 1

of 17

(a)

(b)

(c)

(d)

Solutions of ferous sulphate, zinc sulphate, copper sulphate and aluminium sulphate were separately taken in four test tubes and some iron nails were placed in each of the solutions. After few minutes, it would be observed that the colour of : (a) Solutions of zinc sulphate, copper sulphate and aluminium sulphate

changed and that of ferous sulphate did not change. (b) Solutions of zinc sulphate and aluminium sulphate only changed. (c) Copper sulphate solution only changed (d) All the four solutions changed

31.

FeSO4

(a) (II) (b) III (c) I (d) IV Four test tubes containing solutions are shown along with colours. FeSO4 is

contained in :

(a) (II) (b) III (c) I (d) IV

1

32.

(a) 20 (b) 5 (c) 2 (d) 0.2

The readings of current flowing through a conductor and the potential difference

across its two ends are shown in the ammeter and voltmeter given below. The

1

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resistance of the conductor would be :

(a) 20 (b) 5 (c) 2 (d) 0.2

33. I II

(a) I 2V II 0 V

(b) 0 V

(c) 2 V

(d) I 0 V II 2 V

For the circuits shown in figures I and II, the voltmeter reading would be :

(a) 2V in circuit I and 0 V in circuit II (b) 0 V in both circuits (c) 2V in both circuits (d) 0 V in circuit I and 2V in circuit II

1

34. 0 5 50

(a) 10 A (b) 27 A (c) 0.1 A (d) 0.01 A An ammeter has a range of (0-5A) ampere and there are 50 divisions on its scale. What is its least count ? (a) 10 A (b) 27 A (c) 0.1 A (d) 0.01 A

1

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35. A B R1 R2

A b1 c1 B d2 c2

X Y A B

(a)

(b)

(c) A B

(d) A B

Two students (A) and (B) connected their two given resistors R1 and R2 in the

manners shown below :

Student A connects the terminals marked b1 and c1 while B connects the

terminals marked d2 and c2 in their respective circuits at the points marked

X and Y.

1

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The equivalent resistance measured by A and B will be : (a) of series combination of the two resistors. (b) of the parallel combination of the two resistors. (c) of series combination for student A while parallel combination of the two

resistors for B. (d) of the parallel combination for A while of the series combination of the

two resistors for B. 36.

I i1 V1

II i2 V2

(a) i1 > i2 ; V1 = V2

(b) i1 > i2 ; V1 > V2

(c) i1 < i2 ; V1 = V2

(d) i1 < i2 ; V1 < V2 In figures given below :

Circuit I : ammeter reads current i1 and voltmeter reads V1.

1

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Circuit II : ammeter reads current i2 and voltmeter reads V2.

The relation between the readings is : (a) i1 > i2 ; V1 = V2 (b) i1 > i2 ; V1 > V2

(c) i1 < i2 ; V1 = V2 (d) i1 < i2 ; V1 < V2

37.

A B

6

(a)

(b) (B)

(c) (A) (B)

(d) (A)

A distarched leaf on a potted plant was covered with (A) black strip and (B) transparent strip of paper as shown in the diagram. After 6 hours of exposure to sunlight, the leaf was removed from the plant and tested for starch. Which of the following will be the correct observation ? (a) Whole leaf turned blue-black. (b) Only (B) portion turned blue-black. (c) Only (A) and (B) portions remained colourless and the rest of the leaf

turned blue-black. (d) Only (A) portion remained colourless.

1

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38.

(a)

(b)

(c)

(d)

Which one of the following is the combination of the relevant materials required for setting up an experiment to show that light is necessary for photosynthesis ? (a) Destarched leaves, strips of black paper, starch solution and iodine

crystal. (b) A potted plant, strips of coloured paper, starch solution, iodine and

potassium iodide. (c) Destarched potted plant, strips of black paper, starch solution and

potassium iodide. (d) Destarched potted plant, strips of black paper and iodine solution.

1

39.

(a)

(b)

(c)

(d)

Cover slip is put on the slide containing the leaf peel very gently to avoid : (a) entry of air bubbles (b) crushing of material (c) oozing of glycerine (d) oozing of stain

40.

(a)

(b)

(c)

(d)

The inner walls facing the stomatal aperture, of guard cells are : (a) thin and the outer walls are thick (b) thick and the outer walls are thin (c) thick and the outer walls are also thick (d) thin and the outer walls are also thin

41. CO2

(a) (b)

(c) (d)

To show that CO2 is released during respiration, we take

(a) dry seeds (b) boiled seeds

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(c) germinating seeds (d) wet seeds 42. CO2

(a) KOH

(b) KOH

(c) KOH

(d) KOH

A student while setting up the experiment to show that CO2 is given out during

respiration made some errors shown in the diagram.

What changes should be made in the set up to get the desired results ? (a) KOH solution should be taken in the small test tube inside the flask and

germinating seeds in the beaker. (b) Water should be taken in the beaker and KOH solution in the flask. (c) KOH solution should be taken in the small test tube inside the flask and

water should be taken in the beaker. (d) Water should be taken in the flask and KOH solution in the small test

tube.

- o O o -

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School Principal




any circumstances.



regard.







of 16

I, 2012


/ SCIENCE

X / Class X

3 90


(i)

(ii)

(iii)

(iv)

(v) 1 3

(vi) 4 7 30

(vii) 8 19 50

(viii) 20 24 70

(ix) 25 42



sections.
















SC2-037

of 16

SECTION-A

1.

In domestic electric circuit, with which wire do we connect a fuse ?

1

2.

Name the two components of central nervous systems in humans.

1

3.

Name one fuel used in nuclear reactor.

1

4.

(i)

(ii)

Barium chloride reacts with aluminium sulphate to give, Aluminimum chloride and Barium sulphate. (i) State the two types in which the above reaction can be classified (ii) Translate the above statement into a chemical equation.

2

5.

Name two metals that start floating after some time when immersed in water and explain why they do so ?

2

6. 12 V 3 , 4, 5 12

12

A battery of 12 V is connected to a series combination of resistors, 3 , 4, 5, and 12 . How much current would flow through the 12 resistor ?

2

7.

Why do two magnetic field lines never intersect each other ?

2

8.

(i)

(ii)

(iii)

In the electrolysis of water : (i) Name the gas collected at the cathode and anode respectively (ii) Why is the volume of one gas collected at one electrode double that at

the other ? Name this gas. (iii) How will you test the evolved gases ?

3

9. X

(i) X

(ii)

(iii)

3

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A metal X acquires a green colour coating on its surface on exposure to air. (i) Identify the metal X and name the process responsible for this change. (ii) Name and write chemical formula of the green coating formed on the

metal (iii) List two important methods to prevent the process.

10. (i)

(ii)

(i) What is meant by the term hydrated salt ? (ii) Give two examples of hydrated salt which are white and state their

chemical formula.

3

11.

Define alloys ? List the properties of alloys that makes them useful over pure metals ? Explain this fact with suitable examples.

3

12. (i) 1200 W 30

(ii) 1 1 4

(i) Calculate the electrical energy consumed by a 1200 W toaster in 30 minutes.

(ii) What will be the cost of using the same for 1 month if one unit of electricity costs Rs 4.

3

13. l

a

State any two factors on which the resistance of a cylindrical conductor depends. Compare the resistance of a conductor of length l and area of cross section a with that of another conductor of same materal but of length and area of cross section half and double respectively of the former.

3

14.

What is a solenoid ? Draw a diagram to show the magnetic field lines around a current carrying solenoid. Mention two ways to increase the strength of the field of a solenoid.

3

15.

List in tabular form, three differences between arteries and veins.

3

16.

State the functions of plant hormones ? Name four different types of plant hormones.

3

of 16

17. (a)

(b)

(i)

(ii)

(a) Draw the structure of neuron and label cell body and axon. (b) Name the part of neuron : (i) Where information is acquired (ii) through which information travels as an electrical impulse.

3

18.

Explain the principle and working of a biogas plant using a labelled schematic diagram.

3

19.

Explain ocean thermal energy and how can it be harnessd. Mention any two limitations in obtaining the energy from the oceans ?

3

20. (a)

(i)

(ii)

(iii)

(b) X Fe2O3

(i) X

(ii) Fe2O3

(a) Which method will you use to reduce the following ? Explain by giving a suitable example.

(i) Oxides of less reactive metals (ii) Oxides of moderately reactive metals (iii) Oxides of highly reactive metals (b) The reaction between metal X and Fe2O3 is highly exothermic and is

used to join railway tracks. (i) Identify metal X and name the reaction (ii) Write the chemical equation of its reaction with Fe2O3

OR

(i) (11), (8), (17) (12)

[ Na2O

MgO

(ii)

(i) Write the electron dot structures for sodium(11) , oxygen (8), chlorine (17) and Magnesium (12) [Number given in parenthesis atomic

number of element ] Show the formation of Na2O and MgO by the transfer of electrons.

(ii) Name the ions present in these compounds ?

5

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21.

A student dropped few pieces of marble in dilute hydrochloric acid, contained in a test tube. The evolved gas was then passed through lime water. What change would be observed in lime water ? What will happen if excess of gas is passed through lime water ? With the help of balanced chemical equations for all the changes explain the observations.

OR

(a) A, B, C, D E

pH 4, 1, 11, 7 9

(i) (ii) (iii)

(iv) (v)

H-

(b)

(i)

(ii)

(a) Five solutions A, B, C, D and E when tested with universal indicator showed pH as 4, 1, 11, 7 and 9 respectively. Which solutions is :

(i) neutral (ii) strongly alkaline (iii) strongly acidic (iv) weakly acidic and (v) weakly alkaline Arrange the solutions in increasing order of H-ion concentration (b) Name the acid and base from which the following salts have been

formed. (i) Sodium acetate (ii) Ammonium chloride

5

22.

(a) 8

(b) 4

(c) 4

(d) 4

(e) A1 A2

5

of 16

Find out the following in the electric circuit given in the figure.

(a) Effective resistance of two 8 resistors in the combination (b) Current flowing through 4 resistor (c) Potential difference across 4 resistor (d) Power dissipated in 4 resistor (e) Difference in readings of ammeter A1 and A2 if any

OR

(a)

(b)

(c) 4 A

60V 120 V

(a) State ohms law. (b) Draw a circuit diagram for the verification of Ohms law. (c) The potential difference between the terminals of an electric heater is

60 V when it draws current of 4 A from the source. What current will the heater draw if the potential difference is increased to 120 V.

23.

(i)

(ii)

Describe briefly an activity to :

(i) demonstrate the pattern of magnetic field lines around a straight

current carrying conductor and

(ii) find the direction of magnetic field produced for a given direction of

current in the conductor. Name and state the rule to find the direction

of magnetic field around a straight current carrying conductor. Draw a

diagram to explain the same activity.

OR

5

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(a)

(i)

(ii)

(iii)

(b)

(a) Name and state the rule to determine the direction of a

(i) Force experienced by a current carrying straight conductor

placed in a magnetic field which is perpendicular to it.

(ii) Magnetic field produced around a current carrying circular loop.

(iii) Current induced in a coil due to its rotation in a magnetic field.

(b) Explain the function of an earth wire ? Why is it necessary to earth

metallic appliances ?

24. (a)

(i) (ii)

(iii) (iv)

(b)

(a) Draw a diagram of human respiratory system and label on it :

(i) larynx (ii) trachea

(iii) lungs (iv) bronchi

(b) Why do the walls of the trachea not collapse when there is less air in it ?

OR

(a)

(i) (ii)

(b)

(c)

(a) Draw a diagram to show open stomatal pore and label on it :

(i) guard cells (ii) chloroplast

(b) State two functions of stomata.

(c) How do guard cells regulate the opening and closing of stomatal pore ?

5

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/ SECTION - B

25.

(i)

(ii)

(iii)

(iv)

(a) (i), (ii) (b) (i), (iv)

(c) (ii), (iii) (d) (iii), (iv)

During the experiment of heating of Ferrous sulphate crystals, four students

recorded their observations as :

(i) green colour, of crystals changes to brown black colour

(ii) brownish yellow gas is evolved

(iii) blue colour of crystals changes to green colour

(iv) smell of burning sulphur is felt

Which of the above observations are correct ?

(a) (i), (ii) (b) (i), (iv)

(c) (ii), (iii) (d) (iii), (iv)

1

26. 10

(a) (b)

(c) (d)

An iron nail is placed in a solution of copper sulphate. The nail is taken out

after 10 minutes. The nail will be found to be covered with

(a) brown deposit (b) black deposit

(c) white deposit (d) gray deposit

1

27.

(a) (b) (c) (d)

1

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A dilute solution of sodium bicarbonate is taken in a test tube and a few drops

of the universal indicator is added to it.

The colour observed will be :

(a) blue (b) yellow (c) orange (d) green

28. X Y pH pH

(a) X Y

(b) X Y

(c) X Y

(d) X Y

A student dips pH papers in solution X and Y and observes that the pH paper

turns blue and orange respectively in them. He infers that :

(a) X is HCl solution, Y is NaOH solution

(b) X is acetic acid, Y is sodium carbonate solution

(c) X is sodium carbonate solution, Y is acetic acid

(d) X is oxalic acid, Y is sodium carbonate solution

1

29. NaOH Zn

(a)

(b)

(c)

(d)

On bringing a lighted match stick near the mouth of the test tube in which

NaOH and Zn react :

(a) the matchstick gets extinguished

(b) the matchstick burns faster

(c) a pop sound is heard

(d) no effect is observed on matchstick

1

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30. I, II, III IV

(a) I II (b) II III

(c) III IV (d) II IV

Four test tubes containing solution of different colour marked I, II, III and IV

are shown below. The test tubes containing copper sulphate solution and

Ferrous sulphate solution, could be the tubes :

(a) I and II (b) II and III

(c) III and IV (d) II and IV

1

31.

(a)

(b)

(c)

(d)

An iron nail was kept immersed in aluminium sulphate solution. After about

an hour, it was observed that :

(a) the solution becomes warm

(b) the colourless solution changes to light green

(c) the solution remains colourless and no deposition is observed on iron

nail.

(d) grey coloured deposit form on iron nail.

1

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32. I, II III

(V) (I)

I II III

(a) I (b) II

(c) III (d)

In the experiment on studying the dependence of current (I) on the potential difference (V), three students I, II, III plotted the following graphs between V and I. The graph that is likely to be correct is / are :

Student-I Student-II Student-III

(a) I only (b) II only (c) III only (d) all the three students

1

33.

(a) 20 (b) 0.024 (c) 24 (d) 0.02 The current flowing through a resistor connected in an electric circuit and the potential difference developed across the ends of it are as show in the diagrams.

The value of the resistance of the resistor is : (a) 20 (b) 0.024 (c) 24 (d) 0.02

1

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34.

(a) A (b) B (c) C (d) D

The correct set up for studying the dependence of the current on the potential

difference across a resistor is :

(a) A (b) B (c) C (d) D

1

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35. R1 R2

- I - II

(a)

(b)

(c) I II

(d) I II

In the circuits given below. The resistors R1 and R2 are connected :

Circuit-I Circuit-II (a) in parallel in both circuits (b) in series in both circuits (c) in parallel in circuit I and series in circuit II (d) in series in circuit I and parallel in circuit II

1

36.

(a)

(b)

(c)

(d)

A student set up electric circuit shown here for finding the equivalent resistance of two resistors in series. In this circuit.

(a) resistors have been connected correctly but the voltmeter has been

wrongly connected. (b) resistors have been connected correctly but the ammeter has been

wrongly connected. (c) resistors as well as voltmeter have been wrongly connected. (d) resistors as well as ammeter have been wrongly connected.

1

of 16

37.

(a) I (b) II

(c) I III (d) II III

Given below is th

C.B.S.E. 2012 Sample Papers for X Science (5 Sets)

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