A plane wave is incident from medium 1 into medium 2. The speed of light in medium 2 is 0.75 times the speed in medium 1. If the angle of incidence is 30°, what is the angle of refraction, approximately, according to Huygens' construction and Snell's law?
Options

Question

A plane wave is incident from medium 1 into medium 2. The speed of light in medium 2 is 0.75 times the speed in medium 1. If the angle of incidence is 30°, what is the angle of refraction, approximately, according to Huygens' construction and Snell's law?

Options

G1 Physics · Accepted Answer

Using Huygens' result, sin i ÷ sin r = v₁ ÷ v₂. Therefore, sin r = (v₂ ÷ v₁)sin i = 0.75×sin30° = 0.375. Thus, r ≈ sin⁻¹(0.375) ≈ 22°. Correct option: B.