Question

A ray of light incident on a ${60}^{\circ }$ angled prism of refractive index $\sqrt{2}$ suffers minimum deviation. The angle of incidence is:

• A. ${70}^{\circ }$
• B. $0^{\circ }$
• C. ${45}^{\circ }$
• D. ${30}^{\circ }$

Answer 1

The correct option is C ${45}^{\circ }$

$\mu =\frac{sini}{sin\frac{A}{2}};\sqrt{2}=\frac{sini}{sin\left(\frac{60}{2}\right)}=\frac{sini}{sin{30}^{\circ }}sini=\frac{\sqrt{2}}{2}=\frac{1}{\sqrt{2}}i={45}^{\circ }$