Question

A ray of light is incident on a glass-slab from air at an angle . Thickness and refractive index of glass-slab are‘t’ and ‘${\mu }_a$ ’ respectively, Find the lateral displacement of the emergent ray respective to incident ray.

• A. 2 cm
• B. 3 cm
• C. 5 cm
• D. 1 cm

Answer 1

The correct option is D

1 cm

(1) sin $\theta$ = $\mu$ sin r

$\frac{\sqrt{3}}{2}$ = $\sqrt{3}$ sin r

r = ${30}^{\circ }$

From the figure;

cos r = $\frac{t}{AB}$ $\Rightarrow$ AB = $\frac{t}{cosr}$

sin ($\theta$ - r) = $\frac{d\left(cosr\right)}{t}$

d = $\frac{sin(\theta -r)}{cosr}$ (t)

d = $\frac{1}{2\times \sqrt{3}}$ (t)
d = 1 cm.