When a mirror with a fixed beam on it is rotated through a certain angle, the reflected beam is rotated through an angle that is
A) four times as large.
B) twice as large.
C) equal to the angle of rotation.
D) none of these

Question

Quizplus · Accepted Answer

When a mirror is rotated through a certain angle, the angle of incidence changes by that angle, but since the angle of reflection equals the angle of incidence, the reflected beam rotates through twice the angle of the mirror's rotation.

When a Mirror with a Fixed Beam on It Is