Describe the phenomenon of wave reflection.

Wave reflection is the process where waves bounce back after hitting a barrier or interface between two media.

In more detail, wave reflection is a fundamental concept in physics, particularly in the study of waves and their behaviours. It occurs when a wave encounters a medium that does not absorb the wave's energy and, instead, bounces the wave back into the original medium. This can happen with any type of wave - be it sound, light, water, or seismic waves.

The law of reflection governs this phenomenon, stating that the angle of incidence (the angle at which the incoming wave hits the barrier) is equal to the angle of reflection (the angle at which the wave is reflected). This law applies to both plane and spherical waves. However, it's important to note that the angles are measured relative to the normal - an imaginary line perpendicular to the reflecting surface at the point of incidence.

Reflection can be either specular (mirror-like) or diffuse depending on the nature of the interface. In specular reflection, each incident ray is reflected, with the reflected ray having the same angle to the normal as the incident ray. This type of reflection is observed on smooth, shiny surfaces like mirrors or calm bodies of water. On the other hand, diffuse reflection is when an incident ray is broken up and reflected in many directions. This happens when the reflecting surface is rough or uneven.

The phenomenon of wave reflection is not only a fascinating aspect of physics but also has practical applications in many areas. For instance, it's used in technologies like radar and sonar to detect objects by sending out waves and analysing the reflected signals. In medicine, ultrasound machines use reflected sound waves to create images of the inside of the body. In seismology, the reflection of seismic waves is used to map the Earth's interior.

In conclusion, wave reflection is a fundamental concept in physics that describes how waves bounce back when they encounter a barrier. It's governed by the law of reflection and can be either specular or diffuse depending on the nature of the reflecting surface.