4.1 Refraction of Light

4.1 Refraction of Light

Definition:

Refraction is the bending of light as it passes from one medium to another due to a change in its speed. This bending occurs because light travels at different speeds in different media. The relationship between the angle of incidence θ₁ and the angle of refraction θ₂ is given by Snell's Law:

n₁ sin θ₁ = n₂ sin θ₂

where:
- n₁ and n₂ are the refractive indices of the first and second media, respectively,
- θ₁ is the angle of incidence,
- θ₂ is the angle of refraction.

Example Problem:

Light passes from air (n = 1.00) into glass (n = 1.50) at an angle of incidence of 30 degrees. What is the angle of refraction?

Solution:

Using Snell's Law:
sin θ₂ = (n₁ sin θ₁) / n₂ = (1.00 sin 30°) / 1.50 = 0.333
θ₂ = arcsin(0.333) ≈ 19.5°
The angle of refraction is approximately 19.5 degrees.