What is the bending of light rays as they pass from one medium to another called?

The bending of light rays as they pass from one medium to another is referred to as refraction. This phenomenon occurs when light travels from one substance to another, such as air to water, and its speed changes due to the different optical densities of the materials involved. When light enters a medium at an angle, its velocity changes and causes the light to change direction, resulting in refraction.

This is a fundamental concept in optics that explains many natural phenomena, such as the apparent bending of a straw in a glass of water or the formation of rainbows through prisms. Understanding refraction is crucial for applications in lenses, optics, and various technologies that rely on light manipulation.