Snell's Law
Describes how light bends when passing between media with different refractive indices.
Variables
Derivation
Derived from Fermat's principle of least time or from the wave nature of light at boundaries.
Your notes
Check value
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- n1 = 1.5 (Refractive index of medium 1)
- θ1 = 3 ° (Angle in medium 1)
- n2 = 3.5 (Refractive index of medium 2)
Result: θ2 = 1.2852347 °
Other optics formulas with the same quantities
- Brewster's Angle (Polarization) shares Refractive index of medium 1, Refractive index of medium 2
Where this formula is listed
- Optics formulas, under Refraction, alongside Apparent Depth.
- In the optics list it comes after Spherical Mirror Focal Length and before Refractive Index.
- Optics formula sheet, one of 34 formulas printed with symbol keys and SI units.
- The full formula index, grouped by category and topic.
Common questions
What is the Snell's Law formula?
Snell's Law is written n₁ sin θ₁ = n₂ sin θ₂. Describes how light bends when passing between media with different refractive indices. It belongs to Optics, under Refraction.
What are the units in n₁ sin θ₁ = n₂ sin θ₂?
In SI units, n₁ is refractive index of medium 1 (dimensionless); θ₁ is angle in medium 1, measured in °; n₂ is refractive index of medium 2 (dimensionless); θ₂ is angle in medium 2, measured in °.
How is the Snell's Law formula derived?
Derived from Fermat's principle of least time or from the wave nature of light at boundaries. The result is n₁ sin θ₁ = n₂ sin θ₂.