HUYGENS WAVE THEORY- LAWS OF REFRACTION

WAVE THEORY:

Christian Huygen, suggested the wave theory of light. Thomas Young, gave strong support to the wave theory of Christian Huygen. Fresnel, who showed that light is a transverse wave. Maxwell, on the basis of mathematical theory of magnetism showed that light is electromagnetic in nature.

REFRACTION:

Refraction is the phenomenon of bending of light(from one medium to  another).

CAUSE: Change in speed of light (from one medium to another).

Snell’s Law:

For a given pair of media the ratio of  sines of angle of incidence and angle of refraction is equal to the ratio of phase velocities (v₁/v₂)   of the two media or equivalently to the indices of refraction .

WAVEFRONT AND WAVELETS:

WAVEFRONT:

WAVEFRONT: Continuous locus of all the particles of the medium which are vibrating in the same phase at any instant.

WAVELETS:

WAVELETS: Each and every point  on a wavefront acts as a source  of new disturbance

HUYGEN’S PRINCIPLE: (Assumptions)

Each and every point  on a wavefront acts as a source  of new disturbance called wavelets.

Secondary wavelets emanating from different points, spread out in all directions in a medium with the speed of light,are mutually interfere.

The forward envelope of the secondary wavelets at that time gives the new wavefront.

EXPLANATION: