Question

Two plane mirrors are inclined to each other at an angle of 60°. A ray of light is reflected first at one mirror and then at the other. What is the total deviation of the ray?

A. 60°
B. 120°
C. 180°
D. 360°

Answer 1

The total deviation of the ray is 120°.

Step-by-step explanation:

When a ray of light is reflected at a plane mirror, the angle of incidence is equal to the angle of reflection. In this case, two plane mirrors are inclined at an angle of 60°. Since the angle of incidence is equal to the angle of reflection, the total deviation of the ray after being reflected first at one mirror and then at the other is twice the angle of inclination between the mirrors. Therefore, the total deviation is 2 * 60° = 120°.