In the ray diagram:

the hatched vertical line on the right represents the mirror
the dashed line is called the normal, drawn at 90° to the surface of the mirror
the angle of incidence, i, is the angle between the normal and incident ray
the angle of reflection, r, is the angle between the normal and reflected ray

The law of reflection states that the angle of incidence equals the angle of reflection, i = r. It works for any angle. For example:

the angle of reflection is 30° if the angle of incidence is 30°
the angle of reflection is 90° if the angle of incidence is 90°

In the second example, if a light ray travelling along the normal hits a mirror, it is reflected straight back the way it came. The reflection of light from a flat surface such as a mirror is called spectacular reflection– light meeting the surface in one direction is all reflected in one direction.

	Created by Andrew Gilmour over 10 years ago

KS3 Physics Slide Set on Reflection & Refraction, created by Andrew Gilmour on 04/06/2016.

Reflection & Refraction