Total internal reflection
A light ray hits the inside face of a semicircular block as follows.
What will happen?
For a small angle of incidence
as angle of incidence ,
angle of incidence continues to ,
Therefore, if angle of incidence > C,
Critical angle and refractive index
A ray of light travelling in the direction EO in air enters a rectangular block.
angle of incidence = 30
angle of refraction = 18
(a) Find the refractive index n of the block.
(b) Find the critical angle C of the ray for the block.
(c) If the ray is incident on surface BC, from which surface and at what angle will the ray
leave the block?