Snell's law is a formula used to describe the relationship between the angles of incidence and refraction, when referring to light or other waves passing through a boundary between two different isotropic media, such as water, glass, and air. The Ratio of Sine of the angle of the incidence to the sine of the angle of refraction is a constant for the light of a given color and for the given pair of Media. This Law is also known as Snell's Law. Learn about Refraction | Incident Ray | Refracted Ray