Reflection & Refraction Explorer
Adjust the angle of incidence with the slider or drag inside the viewport.
Calculations
Live math for the selected lab setup
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Live Values
Lab Setup
Air (n=1.00) → Glass (n=1.50)
Refraction from lower index into higher index medium
Angle of Incidence θi: °
AOI is measured from the surface normal.
Top Medium (n₁):
Bottom Medium (n₂):
What is Snell's Law?
Quick reference for refraction + total internal reflection
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Snell’s Law
n₁·sin(θᵢ) = n₂·sin(θₜ)
• θᵢ and θₜ are measured from the surface normal.
• When light goes from lower n to higher n, it bends toward the normal.
• When light goes from higher n to lower n, it bends away from the normal.
• If |(n₁/n₂)·sin(θᵢ)| > 1, there is no real transmitted angle: Total Internal Reflection.
• For TIR setups, the critical angle is θc = arcsin(n₂/n₁).
n₁·sin(θᵢ) = n₂·sin(θₜ)
• θᵢ and θₜ are measured from the surface normal.
• When light goes from lower n to higher n, it bends toward the normal.
• When light goes from higher n to lower n, it bends away from the normal.
• If |(n₁/n₂)·sin(θᵢ)| > 1, there is no real transmitted angle: Total Internal Reflection.
• For TIR setups, the critical angle is θc = arcsin(n₂/n₁).