Q. Two plane mirrors are perpendicular to each other. A ray after suffering reflection from the two mirrors will be
A) Perpendicular to the original ray
B) Parallel to the original ray
C) Parallel to the first mirror
D) At $45{^\circ}$ to the original ray
Explanation
(b) Here, angular deviation
$\delta = 2\pi - 2\theta$
$= 2\pi - 2\ \times \frac{\pi}{2} = \ \pi$
Hence, final emergent ray is parallel to incident ray.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.