Question

A reflecting surface is represented by the equation Y = 2L/π sin(πx/L) 0 ≤ x ≤ L. A ray travelling horizontally becomes vertical after reflection. The coordinates of the point (s) where this ray is incident is

Answer 1

Correct option: (b)

Explanation:

As the Incident ray is horizontal 0 deg, and reacted ray is vertical 90 deg. 

So the slope at point of reaction should be 90 - 0/2 = 45°

The derivative of equation of mirror surface, we get 

and using equation of mirror surface,