Question

When light reflects from two mirrors that meet each other at a right angle, what can be said about the final reflected ray?

• A. parallel and same in direction
• B. parallel and opposite in direction
• C. perpendicular and same in direction
• D. perpendicular and opposite in direction

Answer 1

Answer: (A), (B)

The correct options are
A

parallel and same in direction

B

parallel and opposite in direction

In triangle ABO,

As the sum of all the angles= 180^o

$\angle BAO$ + $\angle ABO$ + $\angle AOB$ = 180^o

$\Rightarrow$ 90^o-θ₁ + 90^o-θ₂ + 90^o = 180^o
That gives θ₁+ θ₂=90^o

Angle between incident ray and reflected ray= 2(θ₁+ θ₂) = 180^o

So, the outgoing ray is parallel and opposite in direction to the incident ray.