Refraction of Light

IGCSE Physics — Investigate how light bends when passing between materials

Simulation

Click or drag on the top half to change the angle of incidence

Controls

Angle of Incidence (θ₁) 30.0°
Angle of Refraction (θ₂) 19.2°
n₁ 1.00
n₂ 1.52
n₁ sin θ₁ 0.500
n₂ sin θ₂ 0.500
Wavelength 580 nm
⚠ Total Internal Reflection! The angle of incidence exceeds the critical angle.

Key Concepts

Snell's Law: n₁ sin θ₁ = n₂ sin θ₂ — When light passes from one medium to another, the relationship between the angles and refractive indices is constant.

Refraction: Light bends towards the normal when entering a denser medium (higher n) and away from the normal when entering a less dense medium (lower n).

Total Internal Reflection: When light travels from a denser to a less dense medium, there is a critical angle above which all light is reflected back. This only occurs when n₁ > n₂.

Dispersion: The refractive index of a material depends on the wavelength (colour) of light. Violet light (short wavelength) is refracted more than red light (long wavelength). This is why a prism splits white light into a spectrum — each colour bends by a different amount.