Total internal reflection

Definition

Total internal reflection occurs when a light ray traveling in a medium strikes an interface with another medium at an angle greater than or equal to the critical angle. Instead of refracting, the light is reflected back into the original medium.

Related terms

Critical Angle (θc): The minimum angle of incidence at which total internal reflection occurs.

Refraction:

The bending or change in direction of light as it passes from one medium to another.

Prism: A transparent object with flat surfaces that can separate white light into its component colors through refraction.