Maximum angle of deviation of a prism having refractive index $\sqrt{2}$ and angle of prism 75° will be |
$\frac{\pi}{6}$ $\frac{\pi}{4}$ $\frac{\pi}{3}$ $\frac{\pi}{8}$ |
$\frac{\pi}{6}$ |
The correct answer is Option (1) → $\frac{\pi}{6}$ For grazing emergence e = 90° For Snell's law $\frac{\sin r_2}{\sin e}=\frac{1}{\sqrt{2}}$ $\Rightarrow r_2=45^{\circ}$ $\Rightarrow r_1+r_2=75^{\circ} ~~~~~\Rightarrow r_1=30^{\circ}$ Now $\frac{\sin i}{\sin r_1}=\sqrt{2}$ $\sin i=\frac{1}{2} \times \sqrt{2} ~~~~~\Rightarrow i=45^{\circ}$ As $i+e=A+\delta$ $\delta=45^{\circ}+90^{\circ}-75^{\circ}=60^{\circ}$ $\delta=\frac{\pi}{3}$ |