We will learn about the phenomenon of light reflection. For this, we will need the following: a mirror, a disk with marked angles, and a light source (a laser).

What does light reflection mean? It means that when it meets the mirror the light bounces back in the medium where it came from, in another direction.

Consider a light ray coming from a light source, named incident ray. The ray of light that leaves the mirror is known as the reflected ray. The line drawn perpendicular to the surface of the mirror is known as a normal line. The angle of incidence is the angle between the incident ray and the normal line and the angle of reflection is the angle between the reflected ray and the normal line.

We notice the two laws of reflection:

1.The first law of reflection states that the incident ray, the reflected ray, and the normal to the surface of the mirror, all lie in the same plane.

2.The second law of reflection states that the angle of reflection is equal to the angle of incidence.

In this example, the angle of incidence is 30 degrees, so the angle of reflection is also equal to 30 degrees.

If we move the source of the light, and therefore the angle of incidence to 60 degrees, we notice that the angle of reflection changes to 60 degrees.

 There is only one situation in which the light doesn’t change its angle of propagation. When the light ray is sent perpendicular to the mirror, we notice that it comes back on the same path, the angle of incidence/reflection being zero.