What is the term for the bending of light when it strikes an edge?

The term that describes the bending of light when it strikes an edge is diffraction. Diffraction occurs when a wave, such as light, encounters an obstacle or a slit that is comparable in size to its wavelength. As the light encounters the edge, it bends around it, leading to the phenomenon known as diffraction. This effect is particularly noticeable with sources of light that have longer wavelengths, such as lasers or when light passes through narrow slits, causing patterns of light and dark bands due to the interference of the waves.

Refraction refers to the bending of light as it passes from one medium to another, such as from air into water, but it is not specifically about striking an edge. Reflection involves light bouncing off surfaces, while dispersion describes the separation of light into its constituent colors, as seen in a prism. Understanding these distinctions is key to grasping the behaviors of light in different contexts.