Two mirrors are joined together along a common side,the planes of the mirrors separated by the angle θ.If the joined mirrors can be used as a retroreflector when a beam of light strikes both surfaces (one after the other),what is the value of θ?
A)30°
B)45°
C)90°
D)135°

Question

Quizplus · Accepted Answer

A retroreflector works by reflecting light back to its source, regardless of the angle of incidence. This can be achieved by aligning the reflected beam with the incoming beam. When two mirrors are joined along a common side, the angle between them is 90°. Therefore, a beam of light entering the retroreflector at any angle will be reflected back along the same path due to the 90° angle between the planes of the mirrors. Hence, the value of θ should be 90°.

Two Mirrors Are Joined Together Along a Common Side,the Planes