Two plane mirrors make an angle of $30 ^ { \circ }$ with each other. A light ray enters the system and is reflected once off of each mirror. Through what angle is the ray turned?
A) 60°
B) 90°
C) 120°
D) 150°

Question

Quizplus · Accepted Answer

When a ray of light reflects off a plane mirror, it is reflected at the same angle as the angle of incidence. Therefore, when the light ray enters the first mirror and reflects off at an angle of 30°, it will be reflected off the second mirror at the same angle of 30°. The total angle turned by the ray of light is the sum of the angles of incidence and reflection, which is 30°+30°=60°. Therefore, the answer is choice A) 60°.

Two Plane Mirrors Make an Angle Of 30∘30 ^ { \circ }30∘

Two Plane Mirrors Make an Angle Of $30 ^ { \circ }$