Question

A light ray is moving from glass to air. Calculate the critical angle for the glass-air interface? Given, _aμ_g = 1.5.

Answer 1

Given:

Refractive index of glass with respect to air (_aμ_g) = 1.5

Formula:

Sin C = `1/(""_aμ_g)`

Sin C = `1/1.5`

Sin C = `10/15`

Sin C = `2/3`

Sin C = 0.6667

C = sin⁻¹ (0.6667)

C ≈ 41.8°

C ≈ 42°

The critical angle for the glass–air interface is 42° (approximately).