Question

A light ray is incident on a transparent sphere of index $=\sqrt{2}$ , at an angle of incidence $={45}^{\circ }$. What is the deviation of a tiny fraction of the ray, which enters the sphere, undergoes two internal reflections, and then refracts out into air?

• A. ${270}^{\circ }$
• B. ${240}^{\circ }$
• C. ${120}^{\circ }$
• D. ${180}^{\circ }$

Answer 1

The correct option is A ${270}^{\circ }$


Using snell's law $n_1\sin i=n_2\sin r$
$\Rightarrow 1\sin {45}^{\circ }=\sqrt{2}\sin r$
$\Rightarrow r={30}^{\circ }$
Deviation ${270}^{\circ }$ anticlockwise.