Question

In a plane mirror, which is the measure of the angle of incidence—the angle between the mirror and the incident ray, or 90° minus the angle between the mirror and the incident ray?

Answer 1

The angle of incidence is defined as the angle between the incident ray and the normal to the mirror. The angle of the incidence can also be obtained by obtaining the angle, 90° minus the angle between the mirror and the incident ray, which is actually equal to the angle between the incident ray and the normal to the mirror.