What is the term for the bending of an electromagnetic wave when it transitions between different media?

The term that describes the bending of an electromagnetic wave as it passes from one medium to another is refraction. This phenomenon occurs because electromagnetic waves travel at different speeds in different media. When a wave enters a medium where it travels more slowly, it bends toward the normal line (the imaginary line perpendicular to the surface at the point of entry). Conversely, when it exits into a medium where it travels faster, it bends away from the normal.

Refraction is a crucial concept in various applications, such as in lenses used in glasses and cameras, where the bending of light is utilized to focus images. It is also responsible for phenomena like the apparent bending of a straw in a glass of water.

The other terms listed relate to different aspects of wave behavior. Reflection refers to the bouncing back of waves when they encounter a barrier, diffraction involves the spreading out of waves as they pass through an opening or around obstacles, and transmission is the process of waves passing through a medium without being absorbed. Understanding these distinctions underscores why refraction is specifically the term that pertains to the bending of waves transitioning between different media.