question_answer

Two plane mirrors are inclined to each other at angle \[60{}^\circ \]. Ray incident on first mirror parallel to the second mirror becomes parallel to first mirror after reflection. Angle of deviation is

A) \[30{}^\circ \]

B) \[60{}^\circ \]

C) \[90{}^\circ \]

D) \[120{}^\circ \]

Correct Answer: D

Solution :

The angle of deviation \[={{180}^{o}}-{{60}^{o}}\] \[={{120}^{o}}\]