Question

A ray of light is incident on a plane mirror at an angle of 40 degrees with the mirror surface. What will be the angle of reflection?

a) 40 degrees

b) 50 degrees

c) 90 degrees

d) 150 degrees

Answer 1

a) 40 degrees

When a light wave reflects off a mirror, it must obey the

law of reflection - angle of incidence is equal to angle of reflection.

If the angle of incidence is 40 degrees, the angle of reflection is 40

Answer 2

b) 50 degrees

incident angle = reflected angle BUT grazing angle is given as 40 so incident angle taken from the normal at right angles to the mirror is 50