Physics I Unit
Transcript of Physics I Unit
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Chapter - I
PHYSICAL WORLD
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Science
The word SCIENCE originated from a latin
word SCIENTIA, which means To Know.
Today, the beneficiaries of science are not
human beings but also other forms of life.
It is the systematic study of nature and
natural phenomina.
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Scientific Method
Science develops through Scientificmethod.
It involves..
The search of basics of science to as muchdetails and depth as possible.
The use of the knowledge so gained to predict
new phenomena or modify the existing theory.
Observation, Qualitative and Quantitativereasoning, etc
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PHYSICS
Physics is a branch of Natural Science
The word PHYSICS came from Greek.
The meaning of PHYSICS is nature. It explains the diverse physical
phenomena on the lines of different
conservation principles and basic laws.
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PHYSICS
Modern Physics and Classical Physics are the
names of the two domains respectively.
Classical Physics Modern Physica
Mechanics
Thermodynamics
Electrodynamics and Optics
Atomic and Molecular
Physics
Nuclear Physics
Fundamental Particle
Physics
Quantum mechanics
Quantum Electrodynamics
Condensed Matter Physics
and Nano Physics
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Scope and Excitement of Physics
Scope of Physics is truly vast
Covers Magnitude of Physical Quantities
like Length, Mass, Time, Energy, etc
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Length
Length is measured as 10-14m or even less
It is in the nuclear region
Also have distances of the order 1026
m. It corresponds the end of known universe.
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Time
Small measures : 10-22Sec.
It is the time of passage of light across the
nucleus.
Large measures : 10 18Sec
It is the time to cover 1026m travelling with
speed of light.
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Mass
Very small : 10-30kg
It is the mass of electron
Very large : 1055
kg The mass of the whole universe.
Terrestrial phenomena is somewhere
middle of this range.
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Physics, technology and Society
Physics, technology and Society
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PHYSICS, TECHNOLOGY AND SOCIETY
Physics paves the way for tomorrow's
Technology
18thCentury - Theoretical heat engine led
to the discovery of steam engine
19thCenturyWireless communication
Technology led to basic laws of electricity
& Magnetism
20thCenturyStudy of semiconductors
led to the technology of silicon chips, and
nano chips
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FUNDAMENTAL FORCES IN NATURE
Forceis needed to push, pull, throw,
deform, break or even change the motion
of objects.
Pulling forceTension
Pushing forceCompression
In Addition, several kind of forces-
Gravitational, muscular, contact force,frictional, elastic, buoyancy, etc
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FUNDAMENTAL FORCES IN NATURE
Different forces arise from a few
fundamental forces in nature. They are
i. Gravitational Force
ii. Electromagnetic Force
iii. Strong Nuclear Force
iv. Weak Nuclear Force
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FUNDAMENTAL FORCES IN NATURE
Gravitational Force Mutual attraction between any two objects
Universal
Newtons Universal law of Gravitation :
Every object in the universe attract each other
with a force. This force is directly
proportional to their masses and inversely
proportional to the distance between them.
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FUNDAMENTAL FORCES IN NATURE
Gravitational Force It is of long range
It does not depend the intervening medium
Weakest fundamental force
Plays a key role in universal phenomena
formation and evolution of stars, galaxies
and galactic clusters)
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FUNDAMENTAL FORCES IN NATURE
Electromagnetic force
Electric Force / Electrostatic force :
It is the force between two charged particlesat rest.
Attractivefor Unlike chargesand Repuslive
for Like charges
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FUNDAMENTAL FORCES IN NATURE
Electromagnetic force It is the force experienced by a moving
electric charge in a magnetic field
Its also of long range
Does not require any intervening medium
The medium modifies its magnitude
Its nearly 1036 times greater than
gravitational
Dominates in atomic and molecular
phenomena
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FUNDAMENTAL FORCES IN NATURE
Electromagnetic force Effects :
Chemical reactions, thermal and other
properties of materials, Tension, Friction,elastic force, etc
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FUNDAMENTAL FORCES IN NATURE
Strong Nuclear Force Force between protons and neutrons
It binds them in the nucleus
Strongest fundamental force
100 times grater than electromagnetic force
Charge independent
Electron doesnot experience this force
Its of short range
Its responsible for nuclear stability
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FUNDAMENTAL FORCES IN NATURE
Weak Nuclear Force Appears only in some nuclear processes
Eg : decay
During this, the nucleus emits one electronand a neutrino (uncharged).
Greater than gravitational force
Smaller than strong nuclear force Range within the nucleus
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FUNDAMENTAL FORCES IN NATURE
A COMPARISON
Force RelativeStrength
Range Operates among
Gravitational
Force
10-38 Infinite All objects in the
Universe
Electromagnetic
Force
10-2 Infinite Charged
Partilcles
Strong Nuclear
Force
1 Very
short
Nucleus
Weak Nuclear
Force
10-13 Very
short
Elementary
Particles