Snell’s law
n₁ sin θ₁ = n₂ sin θ₂; solve θ₂, θ₁, n₂, or n₁.
Calculator
How to use
Snell
TIR appears when sin θ₂ would exceed 1.
Educational use only. Check signs, units, and modeling assumptions (e.g. flat Earth g, no air resistance unless stated).
n₁ sin θ₁ = n₂ sin θ₂; solve θ₂, θ₁, n₂, or n₁.
TIR appears when sin θ₂ would exceed 1.
Educational use only. Check signs, units, and modeling assumptions (e.g. flat Earth g, no air resistance unless stated).
Model / formula
n₁ sin θ₁ = n₂ sin θ₂
Result
θ₂ = 28.9011°