Question

A light ray is incident upon a prism in minimum deviation position and suffers a deviation of $34^{\circ }$. If the shaded half of the prism is knocked off, the ray will

• A. Suffer a deviation of $34^{\circ }$
• B. Suffer a deviation of $68^{\circ }$
• C. Suffer a deviation of $17^{\circ }$
• D. Not come out of the prism

Answer 1

Answer: (C)

By formula $\delta =(n-1)A$
$\Rightarrow 34=(n-1)A$ and in the second position ${\delta }^{\prime }=(n-1)\frac{A}{2}$
$\therefore \frac{34}{{\delta }^{\prime }}=\frac{(n-1)A}{(n-1)\frac{A}{2}}$ or ${\delta }^{\prime }=\frac{34}{2}=17^{\circ }$