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

Options

A. `30^(@)`
B. `90^(@)`
C. `0^(@)`
D. `45^(@)`

Answer

C

Explanation

Angle of prism, `A=30^(@), i=60^(@)`
angle of deviation, `delta=30^(@)`
Using formula, `delta=i+e-A`
`rArr e=delta+A-i`
`=30^(@)+30^(@)-60^(@)=0^(@)`
`therefore" "` Emergent ray will be perpendicular to the face So it will make angle `90^(@)` with the force through which it emerges.