Question

Draw an accurate diagram to show how a ray of light incident on a plane mirror at an angle of 40° to the surface of the mirror is reflected from it. What is the angle between the incident ray and the reflected ray?

Answer 1

Given:
Angle of incident ray with the mirror = 40°
Therefore,
Angle of incidence = Angle of incident ray with the normal = 90°$-$ 40°
= 50°

We know that angle of reflection is always equal to angle of incidence. Therefore, we have:
Angle of reflection = Angle of reflected ray with the normal = 50°
Hence, angle between the reflected ray and the incident ray = 50° + 50° = 100°