Q. Two plane mirrors are inclined to each other such that a ray of light incident on the first mirror and parallel to the second is reflected from the second mirror parallel to the first mirror. The angel between the two mirrors is
A) $30{^\circ}$
B) $45{^\circ}$
C) $60{^\circ}$
D) $75{^\circ}$
Explanation
(c) Let the angle between the two mirrors be$\theta$, Ray $PQ$ is parallel to mirror $M_{1}$ and $RS$ is parallel to $M_{2}.$
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So, $\angle M_{1}\ RS\ = \angle ORQ = \angle\ M_{1}\ OM_{2} = \ \theta$
Similarly, $\angle M_{2}QP = \angle OQR = \ \angle M_{2}OM_{1} = \theta$
$\therefore$ In $\mathrm{\Delta}\ ORQ,\ 3\theta = 180{^\circ}$
$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \theta = 60{^\circ}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.