Bending Light

Explore refraction, reflection, and Snell's Law

Light bends when it crosses a boundary between materials with different indices of refraction. Snell's Law quantifies this: n₁sinθ₁ = n₂sinθ₂. When light travels from a denser medium to a less dense medium at an angle greater than the critical angle, total internal reflection occurs — the basis for fiber optics. The speed of light in a medium is c/n.