Question

A circular beam of light of diameter d = 2 cm falls on a plane surface of glass. The angle of incidence is 60ŗ and refractive index of glass is m =$\frac{3}{2}$. The diameter of the refracted beam is

• A. 4.0 cm
• B. 3.0 cm
• C. 3.26 cm
• D. 2.52 cm

Answer 1

Answer: (C)

3.26 cm

Answer 2

d₁ = PQ cos 60⁰

d₂ = PQ cos r

$\frac{\mathbf{d}_{\mathbf{1}}}{\mathbf{d}_{\mathbf{2}}}$=$\frac{1}{2\cos r}$

d₂ = 2d₁ cos r

1 × sin i = m sin r

sin r =$\frac{\sin 60º}{\mu}$=$\frac{1}{\sqrt{3}}$ Ž cos r =$\sqrt{\frac{2}{3}}$

d₂ = 2 × 2 × $\sqrt{\frac{2}{3}}$= 3.26 cm