Question

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 ${45}^o$ to the original ray

Answer 1

The correct option is B parallel to the original ray

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.