Question

A ray of light is incident at an angle of `60^(@)` on one face of a prism of angle `30^(@)`. The ray emerging out of the prism makes an angle of `30^(@)` with the incident ray. The emergent ray is
A. normal to the face through which it emerges
B. Incline at `30^(@)` to the face through it emerges
C. inclined at `60^(@)` to the face through it emerges
D. None of these

Answer 1

Correct Answer - A
(a) Deviation of ray in prism is given by,
`delta=i+e-A`
So, `e=delta+A-i=30^(@)-60^(@)=0^(@)`
So, emergent ray will be perpendicular to face, or emergent ray will make an angle of `90^(@)` with the face through which it emerges.