A ray of light falls on a plane mirror. When the mirror is turned, about an axis at right angle to the plane of the mirror through `20^(@)` , the angle between the incident ray and new reflected ray is `45^(@)` . Find the angle between the incident ray and original reflected ray

Options

A. `15^(@)`
B. `30^(@)`
C. `45^(@)`
D. `60^(@)`

Answer

C

Explanation

When mirror is rotated through an angle `theta` abount an axis in the plane of mirror, then reflected ray is rotated through an angle `2theta`.
When mirror is rotated about an axis perpendicular to the plane of mirror. The angle of incidence and angle of reflection does not change.
Hence, option (c ) is correct.