Question

A ray incident on a plane mirror is reflected in a direction such that the angle between the incident and the reflected ray is 90 degree. What are the angles of incidence and reflection?

Answer 1

We know that angle of incidence is equal to angle of reflection.

Angle form between the incident and reflected ray= 90 degree {Given}

Let the angle of incidence be y and angle of reflection be also y {as angle of incidence = angle of reflection}

y+y= 90

or, 2y = 90

or, y = 90/2

or y = 45 degree

So angle of incidence and angle of reflection are both 45 degrees each