Snell's Law

Snell's law

also known as the law of refraction, describes the behavior of light passing through the interface between two transparent media planes. As shown in the figure below, when light enters the interface between medium 1 and medium 2, the law states that the incident ray, refracted light, and interface normal are all in the same plane.

In Real Life

When light enters another medium (such as water or glass) from one medium (such as air), the propagation speed changes, leading to a change in the direction of propagation. This phenomenon is called refraction.

• If it enters a denser medium, the light is deflected towards the normal.

• If entering a more sparse medium, the light is deflected away from the normal.