Critical Angle — FormulaEasyQuestion 20213
Question
Critical angle θ_c for a glass-air interface (n_glass = n) is:
- Asin⁻¹(n)
- Bsin⁻¹(1/n)Correct
- Ccos⁻¹(n)
- Dtan⁻¹(n)
Correct answer
sin⁻¹(1/n)
Explanation
At critical angle: n sinθ_c = 1 × sin90° = 1 → sinθ_c = 1/n → θ_c = sin⁻¹(1/n).