What is the principle of wave refraction?

Wave refraction is the bending of waves as they pass from one medium to another.

When waves encounter a boundary between two different media, such as air and water, their speed and direction change. This causes the waves to bend, or refract. The amount of bending depends on the angle at which the waves approach the boundary, as well as the difference in speed between the two media.

If the waves approach the boundary at a perpendicular angle, they will not refract and will continue in a straight line. However, if the waves approach at an angle, they will bend towards or away from the normal, which is an imaginary line perpendicular to the boundary.

When waves move from a medium with a higher speed to a medium with a lower speed, such as from air to water, they will bend towards the normal. Conversely, when waves move from a medium with a lower speed to a medium with a higher speed, such as from water to air, they will bend away from the normal.

Wave refraction has important implications for the behaviour of waves in the natural world. For example, it can cause waves to focus or spread out, and can also cause waves to break at an angle to the shore. Understanding wave refraction is therefore crucial for predicting and mitigating the effects of waves in coastal environments.