Snell's Law: Index of Refraction n₂

Measure θ₁ in air and θ₂ in glass; n₁ sin θ₁ = n₂ sin θ₂, with n₁ = 1, fit sin θ₂ vs sin θ₁ with slope 1/n₂.

School· 20 min·Related simulator: Refraction

Goal

Determine n₂ for glass from multiple incident angles.

Equipment

  • Air–glass interface
  • Protractor (sim)

Theory

Snell: sin θ₂ = (n₁/n₂) sin θ₁, line through origin in (sin θ₁, sin θ₂) plane, slope 1/n₂.

Procedure

  1. Change the incident angle; record (θ₁, θ₂) in degrees with small noise.
  2. Convert sines in the table; fit sin θ₂ vs sin θ₁; n₂ = 1/slope (n₁ = 1).

Experiment

Conclusion

n₂ is consistent with the glass model.