## What is diffraction? Explain.

Diffraction The rhythmic variations in intensity and the bending of light around the corners of an obstacle or the encroachment of light into the region of geometrical shadow constitute a class of phenomena known as the diffraction of light.

## What are the Newton’s rings and how are they formed?

Newton’s rings and its formation :  When a Plano-convex lens of long focal length is placed on a plane glass plate, a thin film of air is enclosed between the lower surface of the lens and the upper surface of the plate. The thickness of the air film is very small at the point of … Read more

## What is fringe width?

Fringe width  The distance between any two consecutive bright or dark fringe is known as fringe width. Symbolically the fringe width is β and

## Why two independent source of light can not produce interference?

Two independent sources of light can not produce interference because a large number of difficulties are involved. The two sources may emit light waves of largely different amplitude and wave length and the phase difference between the two may change with time. That’s why interference of light is produced by two coherent sources which are … Read more

## What do you mean by coherent sources? How are they realized in practice?

Coherent sources Two sources are said to be coherent if they emit light waves of same frequency, nearly equal amplitude and are always in phase with each other. Realization in practice In practice it is not possible to have two independent sources which are coherent. But for experimental purpose, two virtual sources formed by a … Read more

## Define and explain interference of light.

Interference of light:  Wave emitted from two coherent sources having the same wavelength, equal or nearly equal amplitude when passes through a point in a medium, then superposition takes place.  During superposition, if the two waves reaching the point in the same phase then the intensity will be maximum that is bright. But if the … Read more

## Explain Huygens principles.

Huygens principle To explain the propagation of light through ether, Huygens proposed the following principles for the construction of a wavefront at a subsequent time from the known position of the wavefront at any given instance. Every point on a primary wavefront may be considered as the secondary source of disturbance. Secondary waves or wavelets … Read more

## What are transverse and longitudinal waves?

Transverse waves:   In transverse wave motion, the particles of the medium vibrate at right angles to the direction of propagation of wave. Example: Light waves are transverse waves.             Longitudinal wave motion:  In longitudinal wave motion, particles of the medium vibrate along the direction of propagation of the wave. Example: Sound waves are longitudinal waves.

## What are stationary waves?

Stationary waves:  When two simple harmonic waves of the same amplitude, frequency and time period travel in opposite directions in a straight line, the resultant wave obtained is called a stationary or a standing wave. The formation of stationary waves is due to the superposition of the two waves on the particles of the medium.

## Define wave motion?

Wave motion:  Wave motion is a form of disturbance produced in the medium by the repeated periodic motion of the particles of the medium. Here, only the waves travel forward whereas the particles of the medium vibrate about their mean positions.