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Title: immad's notes
Description: all question answers of physics of class matric....
Description: all question answers of physics of class matric....
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Introduction to Physics
CHAPTER – 1
DEFINITION OF PHYSICS
The science of the nature
...
The department of natural science (Physics) which treats the
causes (Electricity, Head, Light, Magnetism) that modifying the general properties of body; natural
philosophy
...
BRANCHES OF PHYSICS
There are many branches of physics:
1
...
”
2 Kinemetics
“It is the branch of Physics which deals with description of motion without reference to any
opposing or external force”
...
Optics
“It is the branch of Physics which deals with light and its properties
...
Dynamics
“It is the branch of Physics which deals with causes of motion and their effects”
5
...
6
...
7
...
CONTRIBUTION OF MUSLIMS SCIENTISTS
1
...
D)
INTRODUCTION
He was born in Basra a city of Iraq
...
He was a freat
scholar of physics,mathematics,engineering,astronomy and medicine
...
2, He also gave the structure and working of eyes
...
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
...
AL-BERUNI
INTRODUCTION
He was born in Berun a small town of Afghanistan
...
t
...
2, He determined the densities of various metals
...
4, He also awarded that he was a first who said that the velocity of light is more than the velocity of
sound
...
MUHAMMAD IBNE MUSA KHAWRZMI
INTRODUCTION
Abu Abdullah Muhammad Ibn Musa al-Khwarizmi was born in 850A
...
CONTRIBUTION
1, Al-Khwarizmi was one of the greatest mathematicians ever lived
...
He is also famous as an astronomer and geographer
...
3, Al-Khwarizmi also developed the calculus of two errors, which led him to the concept of
differentiation
...
4, Al-Khwarizmi wrote a book on astronomical tables
...
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
...
Measurements
CHAPTER – 2
Definitions
1
...
Length is a fundamental unit used for measurements of length, distance and height
...
2
...
Kilogram is a fundamental unit used for measurements of mass
...
Second
It is equal to the duration of 9,192,631,770 periods of radiation of Cesium-133 in ground state
...
These are given below:
1
...
Kilogram (kg): mass (m)
3
...
Ampere (A): electric current (I)
5
...
Mole (mol): amount of substance (n)
7
...
1
...
Cubic meter (m3): volume (V)
3
...
Kilograms per cubic meter (kg/m3): mass density (p)
5
...
Radians per second (rad/s): angular velocity (w)
7
...
Newton (N) (kg
...
Pascal (Pa) (N/m2): pressure (P)
10
...
m): work (W), energy(E), quantity of heat (q)
11
...
Coulomb (C) (A
...
Volt (V) (W/A): potential difference (V), electromotive force (E)
14
...
Farad (F)(A
...
Weber (Wb)(V
...
Henry (H) (V
...
Volts per meter (V/m): electric field strength (E)
19
...
Tesla (T) (Wb/m2): magnetic flux density (B)
21
...
Joules per kilogram Kelvin: (J/kg
...
1mm
...
The
vernier scale (VS) slides over the main scale (MS)
...
Least count of the vernier calipers is calculated by
L
...
01mm
...
The circular scale rotates over the main scale
...
Least count of the screw gauge is calculated by:
L
...
Physical Balance
A physical balance is an instrument that is used to find the mass of an object
...
Stop Watch
A stop watch is an instrument that is used to measure accurately the time interval for any physical event
...
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
...
Scalar and Vectors
CHAPTER – 3
SCALAR
“Scalar quantity are those physical quantity which are completely specified by their
magnitude express with suitable unit
...
”
OR
” Scalar quantity are those physical quantity which require magnitude , express with
suitable unit only is called scalar quantity
...
2, Two scalars are equal if they have same unit
...
(positive negative)
EXAMPLE
Mass,Distance,Temperature,volume,speed e
...
c
VECTOR
“VECTOR quantity are those physical quantity which do not require only their magnitude
express with suitable unit
...
”
OR
” vector quantity are those physical quantity which require magnitude , express with
suitable unit as well as proper direction is called vector quantity
...
2, It can be added,subtracted,multiplied,divided according to the some speciall rules like
head and tail rule,Graphical method e
...
c
...
REPRESENTATION
It can be represented by an arrow with headline
...
1)
————————————->
(figure 1
...
t
...
HEAD AND TAIL RULE
Suppose we have two vector A and B having the different magnitude and direction
...
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
...
4, The new vector R will be the resultant of the given vector
...
This method is called the head and
tail or tip to tail rule
...
From a point A draw perpendicular to the
horizontal surface OX
...
The line OB
represents its horizontal component and it is denoted by Fx
...
MOTION
“When a body changes its position with respect to its surrounding so the body is said to be in the state of
motion”
...
Linear or Translatory Motion
If a body moves in a straight path so the body is to be in Linear motion or Translatory motion
...
2
...
Example
The blades of a moving fan, The wheel of a moving car
...
Vibratory Motion
To and fro motion about the mean point so the body is to be in Vibratory motion
...
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”
...
SPEED
“The distance covered by a body in a unit time is called speed
...
”
FORMULA
Speed = Distance/Time
or V = S/t
UNIT
The S
...
K
...
or m/s
Kinds Of Speed
1
...
2
...
VELOCITY
“The distance covered by a body in a unit time in a particular direction is called velocity
...
”
OR
“Speed in a definite direction is called velocity
...
I unit of Velocity in M
...
S system is Meter/second
...
Uniform Velocity
If 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
...
Variable Velocity
If 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
...
”
OR
“Acceleration depends upon the velocity if the velocity continously increases or decreases the accelerattion
will be produced
...
Positive Acceleration
If the velocity continously increases then the acceleration will be positive
...
Negative acceleration
If the velocity continously decreases then the acceleration will be negative
...
I unit of Velocity in M
...
S system is Meter/second+square
or m/S2
EQUATION OF MOTION
The relationship of initial velocity, final velocity, acceleration, time,and linear distance
...
e
...
i
...
Acceleration = Change of velocity/time
=> a = Vf – Vi/t
at = Vf – Vi
or Vf = Vi + at ————-(1)
Substituting the average velocity:
Vav = (Vi + Vf)/2 ———–(2)
The distance covered by the body in a unit:
S = Vav/t
Putting the value of Vav from equation 2:
S = [(Vi + Vf)/2] * t
Putting the value of Vf from equation 1:
S = [(Vi + Vi + at)/2] * t
S = [(2Vi + at)/2] * t
S = (Vi + at/2} * t
S = (Vit + 1/2at2) {Here 2 is the square of the time “t”
...
Acceleration = Change of velocity/time
=> a = (Vf – Vi)/t
=> at = Vf – Vi
or t = (Vf – Vi)/a ————-(1)
Subsituting the average velocity:
Vav = (Vi + Vf)/2 ———–(2)
We know that:
Vav = S/t
=> S = Vav * t
Putting the value of Vav from equation 2 and value of t from eq 1:
S = [(Vi + Vf)/2] * [(Vf-Vi)/a]
S = Vi2 – Vf2/2a since {(a+b) (a-b) = a2 – b2}
or 2as = Vf2 – Vi2
ACCELERATION DUE TO GRAVITY OR FREE FALLING OBJECTS
“Galileo was the first scientist to appreciate that, neglecting the effect of air resistance, all bodies in free-fall
close to the Earth’s surface accelerate vertically downwards with the same acceleration: namely 9
...
However
this is due to the attraction of the earth which pulls the object towards the ground”
CHARACTERISTIC OF FREE FALLING BODIES
1, When a body is thrown vertically upward, its velocity continously decreases and become zero at a
particular height During this motion the value of acceleration is negative and Vf is equal to zero (a = -9
...
2, When a body falls back to the ground , its velocity continously increases and become maximum at a
particular height During this motion the value of acceleration is positive and Vi is equal to zero (a = 9
...
3, Acceleration due to gravity is denoted by a and its value is 9
...
4, Equation of motion for the free-falling bodies be written as,
Vf = Vi + gt
h = Vit + 1/2 gt2
2gh = Vf2 – Vi2
Kinematics
CHAPTER – 4
KINEMATICS
DEFINITION
“It is the branch of Physics which deals with description of motion without reference to any opposing or
external force”
...
TYPES OF MOTION
There are three types of motion:
1, Linear or Translatory motion
2, Rotatory motion
3, Vibratory motion
1
...
Example
A bus is moving on the road, A person is running on the ground
...
Rotatory Motion
If a body spins or rotates from the fixed point ,so the body is to be in Rotatory motion
...
3
...
Example
Motion of a spring
...
Example
A book is laying on the table,A person is standing on floor,A tree in the garden
...
”
OR
“The rate of change of distance is called speed
...
I unit of speed in M
...
S system is Meter/second
...
Uniform Speed
If a body covers an equal distance in equal interval of time so the body is said to be in uniform speed
...
Variable speed
If a body does not cover an equal distance in equal inteval of time so the body is said to be in variable speed
...
”
OR
“The rate of change of displacement is called speed
...
”
FORMULA
Velocity = Displacment/Time
or V = S/t
UNIT
The S
...
K
...
or m/s
Kinds Of Velocity
1
...
2
...
ACCELERATION
“The rate of change of velocity is called acceleration
...
”
1
...
2
...
FORMULA
Acceleration = change of velocity/Time
or a = (Vf-Vi)/t
UNIT
The S
...
K
...
FIRST EQUATION OF MOTION
suppose an object moves with initial velocity “Vi” in a time “t” and covers a distance “S” in an acceleration
“a” and the final velocity of an object becomes “Vf”
According to the defination of the acceleration “The rate of change of velocity is called acceleration”
i
...
Acceleration = Change of velocity/time
=> a = Vf – Vi/t
DERIVATION
a = Vf – Vi/t
at = Vf – Vi
or Vf = Vi + at
SECOND EQUATION OF MOTION
According to the definition of the acceleration “The rate of change of velocity is called acceleration”
...
e
...
Dont write this sentence in the examination}
THIRD EQUATION OF MOTION
According to the definition of the acceleration “The rate of change of velocity is called acceleration”
...
8 m/s2″
Example
If a ball is thrown vertically upward, it rises to a particular height and then falls back to the ground
...
8m/s2
, Vf = 0)
...
8m/s2 ,
Vi = 0)
...
8m/s2
...
NEWTON FIRST LAW OF MOTIONS
Newton’s first law of motion is also known as the Law of Inertia
...
EXPLANATION
This law consists of a two parts
(a) When body is at rest
(b) When body is moving with uniform velocity
(a)
...
When we apply a force, it changes its state of rest and starts moving along a straight
line
...
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
...
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
...
If we apply a certain force F
on a mass m, then it moves with certain velocity in the direction of the force
...
In this way if we go on
increasing the fore there will be increase in velocity, which will increase the acceleration
...
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:
...
FORCE
Force 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
...
In simple word we can
also say that force is an agent which changes or tends to change the sate of an object
...
MASS
The quantity of matter contained in a body is called mass
...
K
...
WEIGHT
It is a force with which earth attracts towards its centre is called weight
...
K
...
THIRD LAW OF MOTION
” To every action there is always an equal and opposite reaction ”
EXPLANATION
According 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
...
Examples
We we walk on the ground, we push the ground backward and as a reaction the ground
pushes us forward
...
If a book is placed on the table, it exerts some force on the table, which is equal to the
weight of the book
...
This is the reason thta
the book is stationary on the table and it does not fall down
...
”
Examples
Cover a glass with a post card and place a coin on it
...
If the stroke has been made correctly, the postcard will be thrown
away and the coin will drop in the glass
...
As a result he may fall
...
But the upper portion remains in motion due to
inertia
...
The quantity of matter present in a body is called mass
...
The mass of a body remains constant everywhere and does not change by change in
altitude
...
Mass of a body possesses no direction
...
4
...
Weight
1
...
2
...
It is changed by altitude
...
Weight of a body has a direction towards the centre of the earth
...
4
...
MOMENTUM
“The quantity or quality of motion is called momentum and it is denoted by P”
MATHEMATICAL DEFINITION
“It is the product of mass and velocity
...
One of the consequences of this is that the centre of mass of any system
of objects will always continue with the same velocity unless acted on by a force outside the
system
EXAMPLE
Consider two bodies A and B of mass m1 and m2 moving in the same direction with
velocity U1 and U2 respectively such that U1 is greater than U2
...
If we
apply a very small force of magnitude F by pulling the spring gradually and increase it, we
observe that the block does not move until the applied force has reached a critical value
...
According to Newton’s Third Law of
motion an opposite force balance the force
...
Causes of Friction
If we see the surface of material bodies through microscope, we observe that they are not
smooth
...
When one surface is placed over
another, the elevations of one get interlocked with the depression of the other
...
The opposition is known as friction
...
Normal Reaction (R)
Force of friction is directly proportional to normal reaction (R), which act upon the body in
upward direction against the weight of the body sliding on the surface
...
Nature of Surfaces
Force of friction also depends upon the nature of the two surfaces
...
It is different for the two surfaces in contact
...
Between two equal surfaces, the coefficient of friction will be the same
...
The maximum frictional force (when a body is sliding or is in limiting equilibrium) is equal
to the coefficient of friction × the normal reaction force
...
This frictional force, F, will act parallel to the surfaces in contact and in a direction to
oppose the motion that is taking/ trying to take place
...
As we try to
step forward, we push your foot backward
...
2, Writing with a pencil requires friction
...
3, A nail stays in wood due to frction
4, Nut and bold cal hold due to friction
DISADVANTAGES OF FRICTION
1, In any type of vehicle–such as a car, boat or airplane–excess friction means that extra
fuel must be used to power the vehicle
...
2, The Law of Conservation of Energy states that the amount of energy remains constant
...
The friction of parts rubbing together creates heat
...
Methods of Reducing Friction
Friction can be reduced by the following methods:
1
...
2
...
This id done by
using ball bearings
...
Where sliding is unavoidable, a thick layer of greasing material is used between the
sliding surfaces
...
The front of the fast moving objects, e
...
cars, aeroplanes are made oblong to decrease
air friction
...
Hence, liming friction F(s) is directly proportional to the normal reaction
...
)
=> Fs = uR ………
...
It is known as the coefficient of friction
...
We know that the normal reaction is directly proportional to the weight
of the block, therefore,
R = W = mg
Substituting the value of R in equation (i)
=> Fs = umg
Rolling Friction
If we set a heavy spherical ball rolling, it experiences an opposing force called rolling
friction
...
Rolling friction is much less than the sliding friction
...
Statics
CHAPTER – 6
DEFINITIONS
1
...
2
...
3
...
TORQUE
It is the turning effects of a force about an axis of rotation is called moment of force or torque
...
The magnitude of the applied force
...
The perpendicular distance between axis of rotation and point of application of force
...
Centre of Gravity of Regular Shaped Objects
We can find the centre of gravity of any regular shaped body having the following shapes:
1
...
2
...
3
...
4
...
5
...
Centre of Gravity of Irregular Shaped Objects
We can find the center of gravity of any irregular shaped object by using following method
...
Using the hole A, suspend the plate from a nail fixed horizontally in a wall
...
It will be in a position so that its centre of gravity is vertically below the point of
suspension
...
Draw a line AA’ in the plate along the plumb line
...
Repeat the same process using the second hole B
...
Also repeat this process and use
hole C and get line CC’
...
It is our required point, i
...
e the centre of gravity
...
EQUILIBRIUM
A body will be in equilibrium if the forces acting on it must be cancel the effect of each other
...
Static Equilibrium
When a body is at rest and all forces applied on the body cancel each other then it is said to be in static equilibrium
...
CONDITIONS OF EQUILIBRIUM
FIRST 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
...
”
Sum of torque = 0
STATES OF EQUILIBRIUM
There are following three states of Equilibrium:
1
...
When the centre of gravity of a body i
...
below the point of suspension or support, then body is said to be in stable
equilibrium
...
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
...
3
...
When the centre of gravity of a body lies at the point of suspension, then the body is said to be in neutral equilibrium
...
”
Mathematical Expression
We 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/r
Combining both the equations:
a(c) < v2/r From Newton’s Second Law of Motion: F = ma => F(c) = mv2/r
Where,
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 decreases with the increase in radius of the curved path
...
If a stone tied to a string is whirled in a circle, the required centripetal force is supplied to
it 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
...
”
Explanation
Centrifugal force is actually a reaction to the centripetal force
...
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
...
The aeroplane moving in a circle exerts force in a direction opposite to the pressure of air
...
Law of Gravitation
Introduction
Newton proposed the theory that all objects in the universe attract each other with a force
known as gravitation
...
Hence, two
stones are not only attracted towards the earth, but also towards each other
...
Mathematical Expression
Two objects having mass m1 and m2 are placed at a distance r
...
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)
Work, Energy and Power
CHAPTER – 8
Definitions
1
...
2
...
3
...
4
...
5
...
Work
When a force produces displacement in a body, it is said to do work
...
I System – Joule
C
...
S System – Erg
Explanation
When force is applied in the direction of the displacement we can find the work by using
definition
Work = Force * Displacement
W = F*s
W = Fs
Suppose a man is pulling the grass cutting machine then the direction of the foce and
displacement is not same
...
In this case force is resolved into its components
...
Energy is also measured in Joules
...
It is represented by P
...
and is measured in Joules in System International
...
The spring of a watch when wound up
...
Water stored up in elevated reservoir in water-supply system
...
So,
Work = Force * Distance
W=W*h
Since W = mg, therefore:
W = mg * h
Since work is equal to energy possessed by a body:
P
...
= mgh
Kinetic Energy
Definition
The energy possessed by a body due to its motion is known as the Kinetic Energy of the
body
...
E
...
A railway engine moving at high speed
...
Mathematical Expression
Consider a body of mass m at rest (Vi = 0) on a frictionless surface
...
To calculate the amount of work done, we apply the formula
...
E = 1/2(mv2)
So, Kinetic Energy of a body is directly proportional to the mass and square of velocity
...
It is directly proportional to the square of the velocity
...
Energy possessed by a body by virtue of its motion is known as Kinetic Energy
...
Bodies in motion have Kinetic Energy
...
It is calculated by K
...
Energy possessed by a body by virtue of its position is known as Potential Energy
...
Bodies at rest have Potential Energy
...
It is calculated by P
...
= mgh
Law of Conservation of Energy
Statement
Energy can neither be created, nor destroyed, but it can be converted from one form into
the other
...
Its kinetic energy at that point A
is:
K
...
E = 1/2 m * (0)
K
...
(i)
The potential Energy at point A is :
P
...
E = K
...
E
E(A) = 0 + mgh
E(A) = mgh
Suppose the body is released from this height and falls through a distance x
...
The velocity with which it reaches point B is calculated by using the third
equation of motion:
2gs = Vf2 – Vi2
As we know:
Vi = 0
S=x
Therefore,
2gx = Vf2 – 0
2gx = v2
The kinetic energy at point B is:
K
...
= 1/2 mv2
Substituting the value of v2:
K
...
= 1/2 * m * 2gx
K
...
E = mgh
The height of the body is (h-x):
P
...
= mg(h-x)
The total energy at point B is :
E(B) = P
...
E
...
It means that the total value of energy
remains constant
...
Mathematical Expression
Power = Rate of doing Work
Power = Work/Time
P = W/T
Unit of Power
The unit of Power is Joules per second (J/s) or Watt (W)
...
These
deposits are rapidly decreasing and one day all these resources of energy will be consumed
...
the consumption of two much energy is also having adverse effect on our environment
...
To ensure comfortable living with a neat environment, it is the
responsibility of all of us as individuals to conserve energy
...
Machine
A 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
...
Mechanical Advantage
The ratio between the resistance or weight to the power applied in a machine is called the
mechanical advantage of that machine
...
A
...
A
...
Efficiency
The ratio between the useful work done and the work done on the machine is called
efficiency
...
A = (output/Input) * 100
4
...
5
...
Lever
Definition
Lever is the simplest machine in the world
...
Principle of Lever
In the lever the moment P acts opposite to that of work W
...
If the
magnitude of these moments acting in opposite direction is equal, then the lever will be in
equilibrium
...
A = W/P = AB/BC = Weight Arm/ Force Arm
Kinds of Lever
1
...
Examples
Physical Balance
Handle of Pump
Pair of Scissors
See Saw
2
...
Examples
Door
Nut Cracker
Punching Machine
3
...
Examples
Human forearm
Upper and Lower Jaws in the Mouth
...
Such a slope is called an Inclined Plane
...
A = W/P = l/h = Length of Inclined Plane/Perpendicular Height
Pulley
A pulley consists of a wheel mounted on an axle that is fixed to the framework called the
block
...
The groove in the circumference prevents
the string from slipping
...
Mechanical Advantage of Fixed Pulley
In a fixed pulley, the force P is the applied force and weight W is lifted
...
A = W/P = OB/OB
M
...
The load and weight to be lifted is hung from the
hook of block
...
Such a pulley is called moveable pulley
...
As two segments support the weight, the ffort acting on the weight W is
2P
...
A = W/P
M
...
A = 2
Hence, the mechanical advantage of a moveable pulley is 2
...
”
Kinetic Molecular Theory of Matter
The Kinetic Molecular Theory of Matter has the following postulates:
•
•
•
•
Matter is made up of very small particles called molecules
...
Their
motion can be translatory, vibratory or rotational
...
This force depends upon the distance
between them
...
When a substance is heated its temperature as well as molecular motion increases
...
we can say that when the kinetic energy of the
molecules increases, then temperature of the substance rises
...
He observed that the tiny particles in water are constantly moving in a zigzag
path
...
Explanation
The cause of this tiny particle motion is the rapid motion of the molecules, which collide
with the particles and push them in one direction
...
This process
continues and the motion becomes zigzag
...
These states are discussed below:
1
...
The properties
of solids are given below:
The particles are very close to each other
...
Particles in a solid vibrate to and fro from their mean position
...
Some solids also convert directly into gas on heating
...
Liquid
According to the kinetic theory of matter, liquids have the following properties;
•
•
•
•
They have greater kinetic energy than solids but less than that of gases
...
They move more freely than solids
...
•
•
•
The distance between the molecules is greater than that of solids
...
On cooling, they convert into solid
...
Gas
According to the kinetic molecular theory, gases possess the following properties
...
Their shape and volume are not fixed
...
Their temperature is proportional to their kinetic energy
...
On cooling, they convert into liquid and gases
...
”
If we apply a force to a body, it is stretched
...
The phenomenon of turning back to its original shape is called
Elasticity
...
Since
the molecules in a solid are very close to each other, there exist strong attracting forces
between them
...
Different material
have different elasticity depending on the nature of the material
...
Stress
Definition
“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
...
I or MKS System – N/m2 or Pascal (Pa)
C
...
S system – Dyne/cm2
F
...
S or B
...
Tensile Stress: It is a stress tending to stretch a body
...
Bulk Stress: It is an overall force per unit area, also known as pressure
...
Shear Stress: It is a stress tending to produce an angular deformation
...
This change in the
shape of an object is called strain
...
Types of Strain
Following are some types of strain
...
Tensile Strain: It is a change in length divided by original length
...
Bulk Strain: It is the change in volume divided by original volume
...
Shear Strain: It is equal to the angular displacement produced
...
Statement
“Strain produced is proportional to the stress exerted within the elastic limit
...
Yield Point
the yield point is the point at which the material begins to flow
...
Elastic Region
When the material obey’s Hook’s Law, it is said to be in Elastic Region
...
In this
case stress produces a permanent change in the material
...
Breaking Point
The material breaks at a certain point called the Breaking Point of the material
...
”
Mathematical Expression
According to the definition of YOung’s Modulus:
Young’s Modulus = Sress / Longitudinal Strain
Unit
In S
...
Pressure
Definition
“The perpendicular force per unit area acting on a surface is called pressure
...
I or M
...
S System – N/m2 or Pascal
...
G
...
F
...
S or B
...
Pressure in Liquids
In water or other liquids, the weight exerted on a body or the bottom of the liquid is its
pressure
...
Applications – Hydraulic Press
Pascal’s Principle has the application in Hydraulic press
...
It is
filled with some incompressible liquid
...
Piston B is used to lift the object
...
When piston B moves upward, it compresses any
material placed between the rigid roof and this piston
...
(Diagram)
Pressure in Gases
The kinetic theory enables us to account for the pressure a gas exerts on the walls of its
container
...
Atmospheric Pressure
The atmosphere, because of its weight exerts a pressure on the surface of the earth and on
every object on the earth including human beings
...
Applications of Atmospheric Pressure
The fact that the atmosphere exerts pressure has been put into use in several devices such
as siphons, pumps and syringes
...
”
Mercury Barometer
In the laboratory, the atmospheric pressure is measured by means of a mercury barometer
...
The tube is filled with mercury
...
When the open end is completely immersed in the mercury, the thumb is removed
...
This space is called
vacuum
...
This length always
remains constant even if different diameter tubes are taken
...
Archimede’s Principle
Statement
“When an object is immersed in a liquid, an upward thrust acts upon it, which is equal to
the weight of the liquid displaced by the object
...
It is equal to the up-thrust or weight of the water
displaced by the object
...
A body will sink if it displaces liquid or gas whose weight is less than the weight of the
body
...
Internal Energy
Internal Energy of a body is the sum of all kinetic and potential energy of all molecules constituting
the body
...
Joules
It is the amount of heat required to rise the temperature of 1/4200 kg of pure water from 14
...
5 C
...
Calorie
It is the amount of heat required to rise the temperature of 1 g of pure water from 14
...
5C
...
British Thermal Unit
It is the amount of heat tht is required to rise the temperature of 1 pound of pure water from 63F to
64F
...
It is the total kinetic energy of the body
...
Its unit is Joule
...
It is the average kinetic energy of the body
...
Its units are F, C and K
...
It
occurs in all the three states, i
...
solids, liquids and gases
...
Their ability to expand depends on their molecular structure
...
This results in increase in the distance between them
...
Thermal Expansion of solids can be classified into three types
...
Linear Thermal Expansion
Change in length or any one dimension of a solid on heating is known as LInear Thermal
Expansion
...
Real Expansion
The sum of the observed increase in the volume of a liquid and that of the containing vessel is called
real Thermal expansion
...
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
...
Anomalous Expansion of Water
The increase in the volume of water as its temperature is lowered from 4 C to 0C is known as
anomalous expansion of water
...
In winter, the temperature in the north and south poles of the earth falls
...
Ice continues building up at the surface
while the temperature at the bottom remains at 4 C
...
2
...
In winter, when the
water expands, the rock get broken due to this expansion
...
In cold climate, water supply pipes burst when the water expands on cooling
...
Boyle’s Law
The volume of a given mass of a gas is inversely proportional to the pressure, If the temperature is
kept constant
...
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
...
Charle’s Law
The volume of a given mass of a gas is directly proportional to the temperature, if the pressure is
kept constant
...
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
...
Pressure Law
The pressure of a given mass of a gas is directly proportional to the temperature, if the volume is
kept constant
...
THERMOMETER
The instrument that is used to measure temperature is called a thermometer
...
Ordinary Liquid-in-Glass Thermometer
Introduction
An ordinary liquid-in-glass thermometer is used in a laboratory to measure temperature within a
range of -10C to 110C
...
This bulb is filled
with a liquid, usually mercury or alcohol coloured with a red dye
...
The air from the capillary tube is
also removed
...
A temperature scale is
marked on the glass stem to indicate temperatures according to the various levels of liquid in the
tube
...
Clinical Thermometer
Introduction
A clinical thermometer is a device that is used to find the temperature of the human body
...
Construction
It consists of a glass stem with a capillary tube, having a small bulb at one end
...
The upper end of the capillary tube
is sealed so that the liquid will neither spill nor evaporate
...
The glass stem of a clinical thermometer has a construction in its capillary tube near the
bulb
...
Working
In order to find out the temperature, the thermometer is placed in the mouth or in the arm pit of
the patient
...
A temperature scale is mrked on the glass
stem to indicate temperatures according to the various levels of liquid in the tube
...
Maximum and Minimum Thermometer
Introduction
This thermometer is used to read the maximum and minimum temperatures reached over a period
of time
...
This bulb is connected
through a U-shaped tube filled mercury
...
Working
When the bulb is heated, alcohol in it expands and drives the mercury round towards the other end
of the U-shaped tube
...
On each mercury surface, there is a small iron index provides with a light spring to hold it in
position in the tube
...
The lower end of the index on the left indicates the minimum and that on the right indicates
the maximum temperature
...
1
...
It mostly occurs in solids
...
Convection
Convection is a mode of heat transfer by the actual movement of the bulk of the substance from one
place to another through large distances
...
3
...
Heat energy is carried by
infra red electromagnetic waves from one place to another
...
g
...
When it is heated, it bends with the brass on the outside of the curve because brass
expands more quickly than iron
...
Bi-metal Thermometer
Introduction
A bi-metal thermometer is made of a bi-metallic coil
...
Construction
It consists of a bi-metallic strip in the form of a long spiral
...
Working
When the temperature rises, the bi-metal strip coil itself into an even tighter spiral due to different
expansion rates of the two metals
...
2
...
Construction
In a fire alarm, one end of a bi-metal strip is firmly fixed, while the other is free
...
The other
terminal of the battery is connected with a metallic contact which is just above the free end of the
bi-metallic strip
...
It raises the temperature of the bi-metallic strip and its
free end bends towards the contact
...
Latent Heat of Fusion
The quantity of heat required to transform 1 kg of ice completely melts into water at 0C is known
as Latent Heat of Fusion
...
Effect of Pressure on Melting Point (Regelation)
The melting point of those substances, which expand on freezing, gets lowered when pressure oever
one atmosphere is exerted on them
...
Place it across a block of ice
...
Pressure exerted by the copper
wire lowers the freezing point of ice and the ice beneath the wire melts
...
This energy is conducted
through the copper wire, which helps to melt the ice below the wire
...
This process continues until the wire cuts through the ice
block
...
Experiment
Fill a round bottom flask to half its capacity
...
Invert the flask and pour some cold water on the bottom of the
flask
...
The
reason is that, when the water was boiled, it expelled all the air from the flask
...
Since, no fresh air could enter the flask
the pressure inside the flask lowered
...
Evaporation
The process of change of a liquid into vapour without boiling is called evaporation
...
Nature of Liquid: If the boiling point of a liquid is low, then they evaporate much quickly e
...
Alcohol and Ether
...
Temperature of Liquid: If the surface temperature of a liquid is increased, then rate of
evaporation also increases, e
...
ironing of clothes
...
Surface Area of Liquid: If the surface area of a liquid is increased, then the rate of evaporation
increases, e
...
liquids spread over large areas evaporate more quickly
...
Dryness of Air: If there is more dryness in the air, then the rate of evaporation increases, e
...
in
humid weather, clothes take a longer time to dry
...
Wind speed: If the wind speed is greater, then evaporation rate increases
...
Air Pressure on the Surface of The Liquid: If the pressure on the surface of the liquid is
increased, the rate of evaporation decreases
...
Heat lost by hot body = Heat gained by cold body
Refrigerator
Introduction
A refrigerator is a device that is used to keep fruits, vegetables and other eatables cool
...
Refrigerant
Freon is used as the refrigerant in a referigerator
...
Working
1
...
It is then fed into
the condenser
...
Condensation: In the condenser, the gas is liquified under pressure
...
This gas is then allowed to pass through a valve into the evaporator
...
Evaporation: The pressure in the evaporator is comparatively less than in the condenser
...
This results in cooling the area around the evaporator
...
(Diagram)
The gas is then again fed into the compressor and the process continues
...
Vibration
One complete round trip of a simple harmonic motion is called vibration
...
2
...
3
...
4
...
5
...
6
...
7
...
8
...
This range is
known as audible sound
...
Ultrasonic Sound
Sound with frequency greater than 20000 Hz is known as ultrasonic sound
...
Octave
The interval between a waveform and another of twice the frequency is known as Octave
...
H
...
”
Condition for S
...
M
The conditions for simple Harmonic Motion are given below:
•
•
•
•
Some resisting force must act upon the body
...
Acceleration should be directed towards mean position
...
Examples
Following are the examples of S
...
M:
•
•
•
•
Body attached to a spring horizontally on an ideal smooth surface
...
Motion of a swing
...
Resonance
Definition
“The large amplitude vibration of an object when given impulses at its natural frequency is known
as Resonance
...
Four pendulums A, B, C and D of
different lengths are fastened to the string
...
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
...
This string in turn imparts the same periodic motion to the pendulums
...
Due to the same natural frequency
only A vibrates as the same vibration of E
...
Example
March of Soldiers while Crossing the Bridge
Each bridge has its own natural frequency and marching of soldiers is another vibrating system
...
This may damage the bridge
...
Wave
Definition
” A method of energy transfer involving some form of vibration is known as a wave
...
Experiment
We 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
...
Waves can also be produced on very long ropes
...
Transverse Wave
Definition
“The wave in which amplitude is perpendicular to the direction of wave motion is known as
Transverse Wave
...
”
Example
•
•
Sound Waves
Seismic Waves
Sound
Definition
“A vibration transmitted by air or other medium in the form of alternate compressions and
rarefactions of the medium is known as Sound
...
due to the to
and fro motion of the drum, compressions and rarefactions are produced and transmitted or
propagated in air
...
These compressions and rarefactions are traveled by the particles of the medium and transferred
into the next particles
...
Experiment
(Diagram)
Suspend an electric bell in a jar by its wires through a cork fixed in its mouth
...
Now start removing air from jar with the help of an exhaust
(vacuum) pump
...
This
experiment shows that air or any other medium is necessary for the propagation of sound
...
Similarly when a gun is fired its sound is heard a little after seeing its flash
...
Due to its slow velocity sound lags behind
...
Fire a gun at station A and note the time of sound taken for such distance
...
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
...
Density of the medium
...
Nature of the medium
Characteristics of Sound
The 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
...
Loudness
Definition
“Loudness is the magnitude of auditory sensation produce by sound
...
Factors Effecting Loudness of Sound
Loudness depend on following factors:
Area of Vibration of Body: Greater will be the surface area more will be the loudness
...
Density of Medium: Loudness is directly proportional to the density of medium
...
2
...
”
This is the property of sound by virtue of which we can distinguish between a shrill and grave
sound
...
Relative Motion of Sound: If source and listener both are coming closer pitch will increase
...
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
...
Factors Effecting Quality
Quality depends upon the following factors:
•
•
Phase of the Sound Wave
...
Some of them are
as follows:
•
•
•
•
Continuous noise damages hearing and can result in complete deafness
...
Mental system shows less efficiency due to noise
...
Musical Sound
The sound producing pleasing effect on our ears are called musical sounds
...
In longitudinal waves, particles of the medium vibrate in the direction of the waves
...
The portion of wave in which particles of medium are very close to each other is called
compression
...
Examples of longitudinal waves are sound wave and seismic waves
...
Distance between the centre of two compressions and rarefactions is called wavelength
...
In transverse waves, particles of the medium vibrate in the direction perpendicular to the
direction of wave
...
The portion in which particles of medium are higher than their normal position is called crest
...
Examples of transverse wave are microwaves and radio waves
...
Distance between two crests and troughs is called wavelength
...
Incident Ray
The ray that strikes the surface of the medium is known as Incident Ray
...
Reflected Ray
The ray that is sent back into the same medium after reflection is known as reflected ray
...
Plane Mirror
A flat smooth reflecting surface, which shows regular reflection is known as plane mirror
...
Normal
Perpendicular line on the reflecting surface is known as normal
...
Pole
The centre of the spherical mirror is called pole
...
Angle of Incidence
The angle subtended by the incident ray to the normal is known as angle of incidence
...
Angle of Reflection
The angle subtended by the reflected ray to the normal is known as angle of reflection
...
Center of Reflection
The center of the hollow sphere of which the mirror is a part is called center of curvature
...
Principle Axis
The straight line passing through center of curvature nad the pole is known as principle
axis
...
Principle Focus
The ray coming parallel to principal axis after converges to or diverges from a point, which
is called principle focus
...
Focal Length
The distance between the principle focus and pole of the mirror is called Focal Length
...
Radius of Curvature
The distance between the center of curvature and the pole is called radius of curvature
...
Real Image
The image that can be seen on a screen is known as a real image
...
Virtual Image
The image that cannot be seen on a screen is known as a virtual image
...
Magnification
The ratio between the image height and object height is known as magnification
...
Reflection of Light
Definition
“The process in which light striking the surface of another medium bounces back in the
same medium is known as Reflection of Light
...
The angle of reflection, is equal to the angle of incidence: n 2
...
Kinds of Reflection
There are two types of Reflection:
1
...
Regular reflection occurs when parallel rays of light strike with an ideal smooth plane
surface
...
(Diagram)
2
...
It occurs when parallel rays strike with an irregular rough surface
...
(Diagram)
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 sunlight reaches to each of the leaves of a tree and photosynthesis
takes place on large scale
...
Image Formed by a Plane Mirror
Consider a mirror MM’, AP is an object
...
From P as ray travels and strikes mirror and reflect back to the eye, they appear to
come back
...
Hence P’ is the image of P
...
Characteristics of Image Formed by a Plane Mirror
•
•
•
Image is same in size as that of the object
...
The image formed is virtual and inverted
...
”
Types of Spherical Mirrors
There are two types of spherical mirror:
1
...
Convex Mirror (Diverging Mirror)
1
...
”
Properties
•
•
•
•
The bulging side is polished
...
They converge the parallel rays at a point
...
2
...
”
Properties
•
•
•
•
The bulging side is polished
...
They converge the parallel rays at a point
...
Formation of Image by Concave Mirrors
There are six cases to form an image by concave mirror
...
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
...
Details of Image
•
•
•
•
Formed at F
...
Object Beyond C
(Diagram)
If the object is placed beyond C, rays coming from the object are not parallel
...
Therefore, image is formed
between the focus and center of curvature
...
Small in size
...
Object at Center of Curvature ‘C’
When object is placed at the centre of curvature, the image formed at the same place
...
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
...
Large in size
...
Object at F
(Diagram)
When object is placed at focus the reflected rays become parallel to each other
...
Therefore, we say the image is formed at infinity
...
Extremely Large
Real
Inverted
6
...
But they meet backward
...
Details of Image
•
•
•
•
Formed behind the mirror
...
Some of them are given below:
Shaving: A concave mirror is used to enlarge the image
...
Telescope: The convex mirror is used
...
For Rear View: The convex mirror is used in automobiles
...
Refraction of Light and Optical Instruments
CHAPTER – 14
Definitions
1
...
It is called
emergent ray
...
Emergence Angle
The angle formed by the emergent ray and normal is called emergence angle denoted by
Optical Center
The middle point of the lens is called optical center
...
4
...
5
...
If the object is removed, the
impression of image persists in the eye for about 1/10 second
...
6
...
Its unit is
Dioptre
...
”
Laws of Refraction
•
The incident ray, refracted ray and the normal at the point of incidence all lie in the same
plane
...
This constant is known as Refractive Index
(u)
...
Refractive Index = sin
Refractive Index
The ratio between the sine of the angle of incidence to the sine of angle of refraction is
known as Refractive Index
...
It has three rectangular sides and two triangular
sides
...
Actually at that time, the surface of denser medium acts
as a plane mirror and the incident ray bends in the same medium
...
It is used in Periscope, Optical Fibers and other
instruments
...
In prism the angle between two opposite sides is
90 and other two angles are 45 each
...
Then it
totally reflects to the side BC
...
The angle of incidence should be greater than the critical angle
...
Types of Lenses
There are two types of lenses:
1
...
It is a
converging lens
...
Concave Lens If the lens is thinner in the center and thicker at the edges then it is known
as a concave lens
...
(Diagram)
It has three types:
•
Double Concave Lens
•
Plano Concavo Lens
•
Convex Concave Lens
Formation of Image by Convex Lens
1
...
Details of Image
•
•
Formed at Focus
Real
•
Inverted
•
At opposite side
•
Highly diminished
2
...
Details of Image
•
Between F and 2F
•
Opposite side of Lens
•
Real
•
Inverted
•
Small in size
3
...
Details of Image
•
Real
•
Inverted
•
At 2F
•
Same in size
•
At the opposite side of the Lens
4
...
Details of Image
•
Real
•
Inverted
•
Large in size
•
Opposite side of lens
•
Beyond 2F
5
...
Details of Image
•
Real
•
Inverted
•
Extremely Large
•
Opposite side of Lens
•
At infinity
6
...
Details of Image
•
Virtual
•
Erect
•
Large
•
Same side of lens
•
Beyond the object
Optical Instruments
1
...
Sclera Scelortic
It is a layer enclosed in cavity filled with a fluid called Vitrous Humour
...
2
...
This is coated with black pigments
...
3
...
It is a screen on which image is formed
...
Cornea
It allows light into the eyes
...
5
...
It has a tiny opening at its center called pupil, which
regulates the quantity of light entering the eye
...
Crystalline Lens
This is a lens that automatically contracts and expands, alters the focal length of eye lens
...
Ciliary Body
It holds crystalline lens in the proper position
...
Aqueous Humour and Vitrous Humour
The place between cornea and the lens is filled by a transparent liquid called Aqueous
Humour
...
These liquids serve mainly to keep the
spherical shape of the eye
...
Short Sightedness (Myopia)
If a person can see object placed near, but cannot see distant object, this defect is known as
short sightedness
...
The focal length decreases
making the image to form before retina
...
(Diagram)
2
...
Causes
This defect appears due to decrease in thickness of ball
...
(Diagram)
Removal of Defect
It is removed by sing a convex lens of suitable focal length
...
Astigmatism
It is the defect in which the clear image of an object does not form on the retina
...
Removal
This defect can be removed by using lenses of different focal length
...
Presbyopia
The accommodation power of eye loses by which a person suffers a long sightedness
...
Causes
This defect appears due to loss of accommodation power of the lens of the eye
...
2
...
Construction
It consists of a light proof box with a lens at one end and a photographic plate or film at
other end and a shutter to control the light rays
...
Photographic plate or film saves this image
...
3
...
One tube can slide into other so that
the distance between them can be change
...
The lens near the eye is the larger convex of longer
focal length is called eyepiece
...
The eyepiece is brought close to it so that it comes within its focal length
...
The magnification of a microscope can be varied by using different objectives
...
ASTRONOMICAL TELESCOPE
It is used to see heavenly bodies
...
One tube can slide into
other so that the distance between can be changed
...
(Diagram)
Working
The rays from distant object entering the objective and form a real, inverted and
diminished image A’B’ near the principal focus
...
Thus the eyepiece acts as a
magnifying glass and a virtual, erect and magnified image A”B” is formed by the first
image
...
Real image is formed when rays after reflection actually meet at a point
...
Real image is inverted and can be seen on a screen
...
It has a physical existence
...
Virtual image is formed when rays do not actually meet but appear to diverge from a
point
...
Virtual image is erect and cannot be seen on a screen
...
It does not have a physical existence
...
Dual Nature of Light
Light has dual nature, it behaves not only as a particle (photon) but also as a wave
...
2
...
This
phenomenon is called Dispersion of Light
...
Rainbow
The 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
...
Photons (Quantum)
Photons are tiny packets of energy
...
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
...
When corpuscles strike the retina they make it sense light
...
Velocity of light is greater in denser medium
...
According to this theory:
•
•
•
•
•
Light propagates in space in the form of waves
...
Light does not travel in a straight line but in sine wave form
...
Medium is not necessary for propagation
...
It travels in space as well as a medium
...
How A Rainbow is Formed?
As we know a prism disperses sunlight into a series of seven colours
...
These are appeared as Rainbow
...
Electromagnetic Spectrum
Electromagnetic spectrum is a result obtained when electromagnetic radiation is resolved
into its constituent wavelength
...
Microwaves
These radio waves have shorter wavelength between 1mm and 300 mm
...
Infrared Waves
It has a long range
...
Visible Waves
It has a range of 400 nm to 700 nm
...
These are emitted by hotter start (about
25000 C)
...
Insulators
Those material objects that do not allow charge to pass through them are known as
Insulators or non-conductors
...
Conductors
Those material objects that allow the charge to pass through them are called conductors
...
Semi Conductors
Those material objects that allow some charge to pass through them are called SemiConductors
...
Free Electron
Those electrons that are loosely bound by their atom and can move freely within the
material are called free electrons
...
Dielectric
The medium or space (vacuum) between two charges is said to be dielectric
...
Force of Attraction
When two charges attract each other the force is called force of attraction
...
7
...
It has a positive
sign
...
Equivalent Resistance
The relative resistance that has equal value to the combined value of a resistor of a circuit
is called equivalent resistance
...
9
...
It is denoted
by DC, which is obtained from primary and secondary cells
...
Alternating Current
Such 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
...
11
...
12
...
m
...
13
...
The chemical reaction in this case is reversible
...
Fused Plug
It is a wired plug, which has its own cartilage fuse
...
15
...
16
...
17
...
Electrostatic Induction
When a charged body brought close to another uncharged body then other body gains
some chrge without any touch
...
Gold Leaf Electroscope
An electroscope is a device that can be used for detection of charge
...
The leaves are connected to a conductor to a metal ball or disk out side the case,
but are insulated from the case itself
...
The two leaves become charged and repel each other
...
In either case greater the amount of charge greater would be the diverging in
lens
...
Potential Difference
Definition
“The difference in electrostatic potential between two points in an electrostatic field is
called potential difference
...
Therefore, we say that
“Potential difference is work done or energy stored per unit charge
...
Volt
1 volt potential difference is equal to one joule work done on 1 coulomb charge
...
It is a system of two (or more) plates on which we
can store electric charge
...
(Diagram)
Construction
A parallel plate capacitor has two metallic plates with their stands and a dielectric which is
air or some insulator
...
g
...
Working
When the plates of a capacitor are connected to a voltage source
...
Thus plate A
acquires -q charge
...
Then charging
stops when the potential difference (voltage) becomes the voltage of source
...
Charge stored per unit voltage is called
capacitance
...
Farad
If 1 coulomb charge charge produces a potential difference of 1 volt then capacitance is
equal to 1 Farad
...
m
...
It is equal to the energy
supplied by the source to each unit of charge
...
m
...
m
...
Electric Current
“The rate of flow of charge is called electric current
...
Resistance
Definition
“The ratio of the potential difference across an electrical element to the current in it is
called resistance
...
Unit
The unit of resistance is Ohm
...
•
•
•
Length of Conductor: Resistance increases when the length of conductor is increased
...
Nature of Substance: Resistance also depends upon the nature of the conductor or
substance
...
Mathematical Form
According to this law:
V < I (< represents the sign of proportionality
...
Resistor
The body or thing that offers resistance in an electrical circuit is known as resistor
...
Combination of Resistors
1
...
e
...
Total voltage is equal to the combined voltage or the sum of the voltages of all resistors, i
...
V = V1 + V2 + V3
Total resistance is equal to the sum of all the resistances, i
...
RE = R1 + R2 + R3
Derivation
(Diagram)
As show in the above diagram and according to the properties of combination
...
In Parallel
When resistors are combined in parallel then this combination has the following
properties:
•
•
•
•
Current has different ways to pass through
...
Total current is equal to the algebraic sum of each current, i
...
e I = I1 + I2 + I3
Potential difference (Voltage) is same across each resistor, i
...
V = V1 = V2 = V3
•
•
Resistance is small or less than all combined resistance
...
AC is obtained by a resistor that is connected in series with a source of alternating
current
...
Its direction continuously changes
...
It is obtained by a generator
...
Its transportation from one point to another point is very easy
...
It has a frequency about 40 Hz to 60 Hz
...
No voltage drop takes place in the time of transportation
...
It is not too dangerous
...
It is cheaper than DC
...
It changes very high to low or vice versa
...
It changes its direction continuously as +y and -y
...
DC is obtained by connecting the two ends of a conductor to the terminals of a batter
...
Its direction remains unchanged
...
It is obtained by a chemical reaction
...
Its transportation is very difficult
...
It has no frequency
...
Great voltage drop takes place in the time of transportation
...
It is too dangerous
...
It is expensive
...
It cannot change easily
...
It has no direction
...
(2 represents power)
...
Derivation
According to this law:
W < I2t (Here 2 represents the square of current) => W = I2Rt(Here 2 represents the
square of current)
Power
The rate of doing work is called Power
...
Resistance is the measure of opposition by the conductor to the flow of charge
...
It is the reciprocal of the conductance and is measured in volt per ampere or ohm
...
Conductance of a wire is the ease with which current flows in it
...
It is the ratio of current and potential difference
...
Magnetism and Electromagnetism
CHAPTER – 17
Magnet
Metals like iron, nickel and steel attract each other magnetically
...
Non-Magnetic Substances
Substances that are neither attracted nor repelled by a magnet are called non-magnetic substances
...
Ferromagnetic Substances
A substance which behaves like a magnet in the presence of a strong magnetic field is called a ferromagnetic
substance
...
Hard Ferromagnetic Substances
The ferromagnetic substances which retain their magnetism when removed from the magnetic field are
known as hard ferromagnetic substances
...
2
...
Example is
soft iron
...
It is the region
within which the magnet can exert its magnetic force
...
Single-Touch Method
Take 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
...
Repeat the process several times and the steel bar will be magnetized
...
2
...
Connect the coil to a battery and pass strong current
...
In a similar way, a bar can be magnetized by putting it
inside a solenoid and passing current through the solenoid
...
Demagnetization
There are three methods for demagnetizing magnets
...
Hammering
Magnets can be partially demagnetized by hammering them when they are pointing in the east or west
direction
...
Heating
Magnets loose their magnetism when they are heated strongly
...
Electrical Method
The most efficient method of demagnetizing a magnet is to use n alternating current
...
Pass an alternating current (about 12 V) through it
...
While the current is still flowing
...
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
...
Magnetic Effect of Current
When 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
...
The direction of
the fingers will give me direction of the magnetic lines of force
...
Magnetic Field of a Solenoid
When an electric current is passed through a solenoid a magnetic field is produced which is very similar to
that of a bar magnet
...
The
magnetic field inside a solenoid is very strong because the lines of force are parallel and close to one another
...
Electromagnet
If soft iron is inserted in the core of a solenoid, the magnetic field due to the current in the solenoid is
multiplied by thousands
...
Such a magnet
which can be energized by an electric current is called an electromagnet
...
With the help of
electromagnets, iron from mixture is separated
...
1
...
One end of the winding is connected to a terminal (T1)
...
” A rod is attached
to the armature with its free end having a small hammer that can strike against the bell
...
The electric
circuit is completed by connecting the terminals to a batter and a switch
...
The spring also gets detatched from the screw
...
The attraction disappears bringing back the spring to its original position
...
It again attracts
the armature and this process is repeated as long as the switch is turned on
...
Hence, the bell rings
...
Telephone Receiver
Introduction
A telephone receiver is a device that converts electrical energy into sound energy
...
A diaphragm of magnetic
alloy is positioned in front of the electromagnets
...
This electric current varies in magnitude depending upon
the frequency of the sound waves
...
In this way, the magnetic field strength varies as the current changes
...
The diaphragm therefore vibrates and gives
rise to sound of the same frequency as spoken at the other end
...
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
...
Principle of Galvanometer
The 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
...
Construction
A rectangular coil of wire is wound on a light frame with a pointer attached on the top
...
At both ends of the coil, hairsprings are attached
...
A soft iron cylinder is fixed in the core of the coil to enhance the force of conductor
...
Working
When current passes through the coil a couple of opposite forces are produced and causes the coil to rotate
...
Ammeter
Introduction
A galvanometer having a low resistance in parallel is called as ammeter
...
The
low resistance connected in parallel is called shunt
...
The range for the measurement of current in a galvanometer is very small
...
This resistance by passes a great part of the current
...
This resistance acts as a shunt
...
Voltmeter
Introduction
A galvanometer having high resistance in series is called a voltmeter
...
Working
The potential difference across a resistance is directly proportional to the current passing through it
...
A small potential difference produces a full-scale deflection
in a galvanometer
...
Most of the potential difference drops across the high resistance
...
In order to measure the potential difference, a
voltmeter is always connected in parallel to the circuit components
...
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
...
Semi Conductor
Substances whose electrical resistance lies between those of conductors and insulators are
known as semi-conductors
...
Doping
Mixing of any tetravalent element into a trivalent or pentavalent element so that its
electrical conductivity increases is called dopping
...
n-Type Substance
A pure semiconductor with a valency of three, doped with a pentavalent element is called
n-type semiconductor
...
p-Type Substance
A pure semiconductor with a valency of three doped with a trivalent element is called ntype semiconductor
...
Diode
The common boundary of n-type and p-type regions in a semiconductor is called p-n
junction diode
...
7
...
It has a very low
electrical resistance
...
Reverse Biased
If 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
...
9
...
10
...
11
...
The central part is known as the base (b) and the pieces at either side are
called the emitter (e) and the collector (c)
...
npn Transistor
The npn transistor has a thin piece of p-type substance sandwiched between two pieces of
n-type semiconductors
...
pnp Transistor
The pnp transistor has a thin piece of n-type substance sandwiched between two pieces of
p-type semiconductors
...
Construction
An electric telegraph consists of a battery that is connected to a buzzer through the tapping
key
...
The circuit is
completed by connecting the other terminal to the ground few feet below
...
Working
When the tapping key is pressed, the receiver produces a buzzing sound
...
The international Morse Code, which is a combination of dots and dashes is used to
send and receive messages with the help of telegraph
...
Working
1
...
When someone speaks in the microphone at the radio station, sound waves are converted
into electrical fluctuating current
...
The transmitting antenna
produces radio waves with fluctuating amplitude
...
2
...
This AC is converted into DC with the help of a
rectifier
...
The DC energizes the
electromagnet of the speaker and causes the diaphragm to vibrate
...
Radar
Introduction
Radar stands for Radio Detection and Ranging
...
Construction
It consists of a transmitter, a receiver and several indicating devices
...
Transmission: The transmitter generates very high frequency electromagnetic waves in
the desired direction with the help of a concave antenna
...
Receiving: These rays after striking an object are reflected back and are received by the
radar antenna
...
3
...
They
calculate the wave velocity and finally the distance of the object
...
Telephone
Introduction
A telephone is a device by which two persons at distant places can directly talk to each
other through electric current carrying wires
...
1
...
2
...
Working
1
...
The compressions and rarefactions of the sound waves cause the
diaphragm to increase and decrease the pressure on carbon granules
...
2
...
The diaphragm in front of the electromagnet also
vibrates with different amplitudes and generates sound of same frequency as spoken at the
other end
...
The
convex lens of the TV Camera produces an image on the thin sensitive plate known as
mosaic screen
...
When light is stronger, more electrons are given out the material making positive
at this location
...
Special magnetic deflection system achieves this purpose
...
If the positive
charge is less, more of the electrons are emitted
...
The video signals that have been
amplified are utilized to manufacture very high frequency
...
Nuclear Physics
CHAPTER – 19
Nuclear Physics
It is the branch of Physics that deals with the structure, properties and reaction of particles
found in the nuclei of atoms
...
The substances that emit radiation are known as radioactive elements
...
A photographic plate is placed at some distance above the lead block so that the radiation
from radium falls upon it
...
This chamber is then placed between the poles of a
powerful magnetic field
...
Properties of Alpha Particles
•
•
•
•
•
•
•
Alpha particles are Helium nuclei
...
The velocity of alpha particles is 1/100th of the velocity of light
...
Penetration power is the least
...
It produces florescence with zinc sulphide solution
...
The charge on beta particles is negative
...
Ionization power is less than alpha particles
...
It effects the photographic plate
...
Properties of Gamma Rays
•
•
•
•
•
•
Gamma rays are electromagnetic in nature
...
Its velocity is equal to the velocity of light
...
Its penetration power is the greatest
...
•
It produces florescence with Barium Platino Cyanide
...
Chain Reaction
In a fission reaction, each nucleus emits three neutrons
...
These neutrons
produce further fission in other nuclei and this process continues
...
Nuclear Reactor
A system used to obtain a controlled amount of heat from nuclear fission is called a nuclear
reactor
...
This is called fuel element
...
The fast moving neutrons have to
be slowed down before they cause further fission
...
heavy water is used as a moderator
...
The rate of
chain reaction is controlled by inserting control rods which are commonly made of Boron
...
This heat is used to produce
steam
...
Nuclear Fusion
The process in which two lighter nuclei are brought together to form another heavy
nucleus is called the Fusion Reaction
...
End…
Title: immad's notes
Description: all question answers of physics of class matric....
Description: all question answers of physics of class matric....