Light Refraction Through Glass Block

Refraction occurs when light travels from one medium to another with a different optical density. The light ray bends due to the change in speed as it enters the new medium. This phenomenon is governed by Snell's Law.

When light enters a denser medium (higher refractive index), it slows down and bends toward the normal. When it exits back to a less dense medium, it speeds up and bends away from the normal. In a rectangular block with parallel surfaces, the exit ray is parallel to the incident ray but laterally displaced.