What does refraction refer to?

Refraction refers to the bending of waves as they pass from one medium to another. This phenomenon occurs because waves, such as light or sound, travel at different speeds in different materials. When a wave transitions from one medium to another—like from air to water—the change in speed causes the wave to change direction. This bending can lead to various effects, such as the distortion of images in lenses or the apparent bending of objects submerged in water.

While other options mention related concepts, they do not accurately capture the specific definition of refraction. Sound wave behavior, light diffusion, and frequency changes are all distinct phenomena related to wave mechanics but do not denote the bending aspect characteristic of refraction. Understanding this principle is essential, particularly in applications involving optics, underwater navigation, and other scenarios where wave propagation through different materials is involved.