Wave optics describes the connection between waves and rays of light . According to wave theory of light , the light is a form of energy which travels through a medium in the form of transverse wave motion . The speed of light in a medium depends upon the nature of medium .
Newton ’ s Corpuscular Theory
Light consists of very small invisible elastic particles which travel in vacuum with a speed of 3 x 10 8 m / s .
The theory could explain reflection and refraction . The size of corpuscular of different colours of light are different .
It could not explain interference , diffraction , polarisation . photoelectric effect and Compton effect . The theory failed as it could not explain why light travels faster in a rarer medium than in a denser medium .
Wavefront
A wavefront is defined as the continuous locus of all the particles of a medium , which are vibrating in the same phase .
These are three types ( i ) Spherical wavefront ( ii ) Cylindrical wavefront ( iii ) Plane wavefront