discover everything from nature.....

slide 1

knowledge is power

develop scientific approach...

dream big

learning is continuous process....


combine experiments and theory....

Saturday, 12 November 2016

dictionary of physics

school level dictionary of physics

Aberration is a defect in  the image which is not a true picture of the taken object.
A Phenomenon of wearing off because of friction
Absolute scale
The zero of this scale of temperature corresponds to absolute zero.
Absolute zero
Zero of thermodynamic temperature (0 kelvin)
Absorption hygrometer
A device that is used for measuring the humidity of air
Acceleration due to gravity(g)
It is the uniform acceleration produced in a freely falling body due to the gravitational pull of the earth.
A type of voltaic cell or battery that can be recharged by passing a current through it from an external d.c. supply.
Acceleration (a)
The rate of change of speed or of velocity
A machine used for producing high energy charged particles and studying nuclear reactions.
Materials that are used for doping semiconductors whose atoms accept electrons form neighbouring atoms known as host
Achromatic colour
A colour that has no colour
Refers to the study of the production and properties of sounds
Referes to any of various instruments for measuring the intensity of electromagnetic radiation.
Active device
An electronic component such as a transistor that is capable of amplification
A device that is used for connecting parts of different size and shape
It is a measure of the ability of a circuit to conduct an alternating current.
The process of formation of a layer of molecules of one substance on the surface of a solid
The part of a radio system that transmits energy into or receives from the atmosphere or space
A colloidal dispersion of a solid or liquid in a gas
Air brakes
A system of brakes that is operated by compressed air
Air conditioner
A device that is used for reducing temperature and humidity of air in an enclosed space
It is a gaseous mixture that surrounds the earth.
Alcohol thermometer
A liquid-in-glass thermometer that uses ethanol as its working substance.
The existence of a solid substance in different physical forms.
A mixture of two or more metals or of a metal with small amounts of non-metals.
Used to make permanent magnets.
Alternating current (A.C.)
A current which flows alternately in one direction, then in the opposite direction around a circuit.
Alternating voltage
The voltage whose magnitude and direction change with time and after a certain time the voltage recur with the same magnitude and in the same direction is called alterating voltage
An alloy of mercury with one or more other metals
A meter used to measure electric current.
The ampere is the practical unit of electric current.
It is a unit of quantity of electricity
An electronic device that is used to increase the strength of an input signal applied to it.
The maximum value of a varying quantity from its mean value
A device for determining the plane of polarization of plane-polarized radiation
It is the property of a solid wherein stress and strain are not uniquely related in preplastic range.
It is a device that is used to measure the speed of wind.
Aneroid Barometer
It is a type of barometer
Angle of refraction
The angle between a refracted ray and the normal to the surface at the point of refraction
Unit of length
Angular displacement
Refers to the angular or rotational displacement
Angular frequency
It is equal to the number of complete rotations made by an object per unit time
Angular velocity
It is the rate of change of angular displacement
Negatively charged ion
The process of heating a solid to a temperature below the melting point.
Annular space
The space between two rings (inner and an outer)
The electrode that is a positive potential with respect to the cathode.

Friday, 11 November 2016



            Concept of equation can be understood easily by taking an example.  You are given that, your age is exactly half of your father's age, and the sum of your age and your father age is equal to 60, then find out your age and your father's age. 

         In this example, you are going to equate two values and they are sum of the ages = 60, 

     On the left hand side, you are going to write as, (X/2)+X=60,
                     Where X is your father age,

from this concept, you can understand about equation, equation is equality between two terms in which an unknown term can be found out by solving the equation.

LHS:  Left hand side of the equation
RHS: Right hand side of the equation



Wednesday, 9 November 2016

mathematics - GEO BOARD

Monday, 7 November 2016

two digit multiplication in one minute

images formed by concave mirror

Sunday, 6 November 2016

theories of light

Nature of light : theories of light

Different theories of light:

i) Newton's corpuscular theory of light

ii) Huygen's wave theory of light

iii) Maxwell's electromagnetic theory of light

    iv) Planck's Quantum theory of light

v) De-Broglie's dual theory of light

Newton's corpuscular theory of light:


a) Extremely minute very light and elastic particles are being constantly emitted by all luminous bodies in all directions.

b) These corpuscles travel with the speed of light

c) When these corpuscles strike the retina of our eye then they produce the sensation of vision.

d) The velocity of these corpuscles in vacuum is 3 x  m/s.

e) The different colours of light are due to different size of these corpuscles.

f) The rest mass of these corpuscles is zero.

g) The velocity of these corpuscles in an isotropic medium is same in all directions but it changes with the change of medium.

h) These corpuscles travel in straight lines

i) These corpuscles are invisible.

The phenomenon explained by this theory

a) Reflection and refraction of light

b) Rectilinear propagation of light

c) Existence of energy in light.

but this theory could not explain ......Interference, diffraction, polarisation, double refraction and total internal reflection. Photoelectric effect and compton effect.

defect: Velocity of light being greater in rarer medium than that in a denser medium.


-This theory was enunciated by Huygen in a hypothetical medium known as ether. Ether is that imaginary medium which prevails in all space, is isotropic, perfectly elastic and massless.

-The different colours of light are due to different wavelengths of these waves.

-The velocity of light in a medium is constant but changes with change of medium.

-This theory is valid for all types of waves.

Theory of secondary wavelets

characteristics of this theory.....

*The locus of all ether particles vibrating in same phase is known as wavefront.

*When light travels in a medium then the particles of medium start vibrating and consequently a disturbance is created in the medium.

*Every point on the wavefront becomes the source of secondary wavvelets.  It emits secondary wavelets in all directions which travel with the speed of light.

*The tangent plane to these secondary wavelets represents the new position of wavefront.

The phenomena explained by this theory.....

a) Reflection, refraction, interference, diffraction, polarisation and double refraction.

b) Rectilinear propagation of light.

c) Velocity of light in rarer medium being greater than that in denser medium.

d) Photoelectric effect, compton effect and raman effect.

e) Backward propagation of light ELECTROMAGNETIC THEORY....

This theory was enunciated by Maxwell.


-The waves produced by accelerated charges or oscillating circuits or high frequency A.C. in conductors are known as electromagnetic waves.

-In these waves the electric vector (Ē) and magnetic field vector (B) and the direction of propagation of waves are mutually perpendicular to each other.

-The nature of these waves is transverse.

-these waves can be polarised.

-In these waves electric and magnetic fields vibrate in the same phase i.e. these reach the extreme position and mean position simultaneously.

-these waves propagate in vacuum also.

-the velocity in vacuum is equal to that of light

-their velocity in vacuum is equal to that of light.


This theory was enunciated by Max Planck.

characteristics :

-Light travels in the form of minute packets of energy which are known as quanta or photons.

Photons are emitted discretely and not continuously.

-The energy of photons is given by E=nhv (v-->frequency)

              where n=1,2,3,...

n is the integer and it represents the number of photons.

-The velocity of photons is equal to that of light

-Their rest mass is zero.

-In this theory, the energy of all the photons is same whereas in Newton's corpuscles theory, corpuscles may possess any energy.

- It is stable particle.

-Being uncharged, these are not affected by electric and magnetic fields.

nature of light


Light:  The physical cause, with the help of which our eyes experience the sensation of vision, is known as light.  (or) the form of energy, which excites our retina and produce the sensation of vision, is known as light.

Ray of light:   The path of light energy from one point to another is known as a ray of light.

properties of light:  i) No material medium is required for the propagation  of light energy i.e. it travels even in vacuum.

ii) Its velocity is constant in all inertial frames.  It is independent of the relative velocity between source and the observer.

iii) velocity of light is maximum in vacuum whose value is 3 x  m/s.

iv) Light can emit electrons from the metal surface i.e. it can produce photoelectric effect.

v) Light propagates in straight lines.

vi) Light produce thermal effect and exerts pressure when incident upon a surface.  It proves that the light has momentum and energy.

vii) Light exhibits the phenomena of reflection, refraction, interference, diffraction, polarisation, and double refraction.

viii) The properties of the medium through which light passes remain unchanged.

ix) The velocity of light is different in different media.  In rarer medium, it is more and in denser medium, the velocity of light is less.

Saturday, 5 November 2016


Thursday, 3 November 2016

basic units

physical quantities and their units physical quantity S.I. Unit
1 distance/displacement m
2 radius of gyration m
3 circumference,perimeter m
4 mass Kg
5 period of oscillation sec
6 tiime sec
7 time constant sec
8 frequency hertz(Hz)
9 area m2
10 volume m3
11 density kg.m-3
12 linear density kg.m-1
13 speed, velocity, m.s-1
14 acceleration m.s-2
15 linear momentum kg.m.s-1
16 impulse N.s
17 force N
18 work, energy, PE,KE J or N.m
19 Strain energy J or N.m


watt or J.s-1