Reflection of light

Reflection is the change in direction of light when it bounces off a surface.

Measuring the angle of a ray

There are two types of rays involved in reflection:

• An incident ray is the ray of light that hits the surface.
• A reflected ray is the ray of light that bounces off the surface.

To measure the angles of these rays, we also need to know about the normal:

• The normal is an imaginary line that is perpendicular (at 90°) to the surface where the light ray hits.

Laws of reflection

• The angle of incidence is equal to the angle of reflection.
• This means that the angle at which the light ray hits the surface is the same as the angle at which it bounces off.
• Both the incident ray and the reflected ray are on the same side of the normal.