# PHYS 2212 Module 13.3

## Refraction

Recommended Reading

13.3 Refraction

### Learning Objectives

By the end of this section, you will be able to:

• Describe how rays change direction upon entering a medium
• Apply the law of refraction in problem solving

### The Law of Refraction

If light travels from one medium into another, it will (in general) change its direction. This is called refraction. This fact is a property of waves. Nevertheless, the description of the effect doesn’t need to refer to the wavelength, or wave nature, of light, so this topic still belongs in this geometrical optics chapter. The math involved is fairly straightforward (one equation to learn), and there are many important consequences/applications ranging from simple eyeglass lenses, to fancy telescopes, to medical imaging equipment, fiber optics, etc…

### Snell’s Law (The Law of Refraction)

There is a formula for the refraction of light, which is derivable from Maxwell’s Equations, called Snell’s Law:

Practice!

Practice!