Question

(a) Write the necessary conditions for the phenomenon of total internal reflection to occur.
(b) Write the relation between the refractive index and critical angle for a given pair of optical media.

Answer 1

(a) Conditions for Total internal reflection.

(1) The incident ray should be in denser medium.

(2) The angle of incidence should be in denser medium.

(b) When a light is incident on an interface of a denser and rarer medium and at angle of incidence equal to critical angle then the refracted will be grazing the surface.