Here's a breakdown:

* Incident ray: The ray of light that strikes the barrier.

* Reflected ray: The ray of light that bounces off the barrier.

* Normal: An imaginary line perpendicular to the surface of the barrier at the point where the incident ray strikes.

* Angle of incidence: The angle between the incident ray and the normal.

* Angle of reflection: The angle between the reflected ray and the normal.

The law of reflection states that the angle of incidence is equal to the angle of reflection. This means that the reflected ray bounces off the barrier at the same angle as it hit it.