What is the phenomenon when a wave bounces back after hitting a surface?

The phenomenon where a wave bounces back after hitting a surface is known as reflection. This process occurs when a wave encounters a medium that it cannot pass through, such as a mirror or a wall. When the wave strikes the surface, part of its energy is redirected back into the medium it originated from, resulting in a change of direction without a change in speed. The angle at which the wave hits the surface is equal to the angle at which it reflects away from that surface, which is described by the law of reflection.

In contrast, refraction refers to the bending of waves as they pass from one medium to another, leading to a change in speed and wavelength. Diffraction involves the spreading out of waves around obstacles or openings, and transmission describes the passing of waves through a medium. Each of these phenomena serves distinct purposes in the study of wave behavior, but they are different from reflection, which specifically denotes the bouncing back of waves.