Question

A ray is incident on a mirror at an angle 20with the normal. Now the mirror is rotated 30 about an axis in the plane of the mirror. What will be the angle made between the initial reflected ray and final reflected ray?

Answer 1

AnswEr:—

• Consider a plane-mirror and a fixed incident ray of light reflecting from the surface at an angle .
• Before the mirror has rotated, the angle of incidence is is the angle of reflection. If the mirror is rotated through an angle the normal is rotated by an angle and thus the angle of incidence increases to +.
• The angle of reflection must also increase by tow The difference between the final angle of reflection and the initial angle of reflection and is 2θ.