Snell’s law relates the directions of a ray crossing an interface between two refractive media.
Difficulty
Intermediate
Read time
5 min
Prerequisites
Basic algebra, consistent units, and the stated model assumptions
Source
OpenStax, College Physics 2e, §25.4 (Paul Peter Urone and Roger Hinrichs)OpenFormulaGraph equation reference; FormuLab adaptation details and license are provided below.
Adapted from OpenFormulaGraph, under CC BY 4.0.
FormuLab adapted wording, notation, applicability conditions and topic placement, and expanded the numerical check into a worked example.
Snell’s law relates the directions of a ray crossing an interface between two refractive media. Angles are measured from the surface normal, rather than from the surface itself.
| Symbol | Meaning | Units |
|---|---|---|
| Index of Refraction (incident) | ||
| Incidence angle measured from the normal | ||
| Index of Refraction (refracted) | ||
| Refraction angle measured from the normal |
Find a transmitted ray angle at an interface.
Track paraxial or geometric rays across material boundaries.
A ray enters glass of refractive index 1.50 from air of index 1.00 at angle π/6 rad to the normal. Find the transmitted angle in radians.
OpenFormulaGraph equation reference; FormuLab adaptation details and license are provided below.
Adapted from OpenFormulaGraph, under CC BY 4.0.
FormuLab adapted wording, notation, applicability conditions and topic placement, and expanded the numerical check into a worked example.
Assumptions
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