Question

The angle between the mirror and the incident ray in the case of reflection in a plane mirror is 20 degree. What is the angle of incidence and angle of reflection?

Answer 1

Angle of incidence = angle of reflection
therefore 20 degree

Answer 2

the angle between mirror and incident ray is 20° but incident angle is angle between the normal and incident ray so it is

90-20=70° thus ∠i=70°=∠r