"The angle of incidence is equal to the reflection angle".


It is the phenomenon in which light, when reflecting upon a surface, returns to the environment in which it was initialy propagating. The regular light reflection occurs at regular surfaces, such as mirrors. Diffuse light reflection occurs on uneven surfaces, and it make possible the perception of objects by the eyes.

Illustration of regular and irregular reflection.

Laws of Reflection

Reflection in the plane mirror. An object at point \(P\) is viewed through a mirror in position \(P'\). This is due to reflection of beams from the object on the mirror.

For a light beam reflecting on a surface, we can observe the following:

\(1^{st}\) Law
The incident beam \(\vec{v}\), the reflected beam \(\vec{u}\) and normal \(\vec{N}\) are in the same plane.
\(2^{nd}\) Law
The angle of incidence \(\alpha\) is equal to the reflection angle \(\beta\). (The convention is to always use the angle in relation to a normal line to the surface).