Question

Two identical prisms 1 and 2, each will angles of ${30}^{\circ },{60}^{\circ }$ and ${90}^{\circ }$ are placed in contact as shown in figure. A ray of light passed through the combination in the position of minimum deviation and suffers a deviation of ${30}^{\circ }$. If the prism 2 is removed, then the angle of deviation of the same ray is

• A. Equal to ${15}^{\circ }$
• B. Smaller than ${30}^{\circ }$
• C. More than ${15}^{\circ }$
• D. Equal to ${30}^{\circ }$

Answer 1

The correct option is A Equal to ${15}^{\circ }$

$\delta =(\mu -1)A$ as A is halved, so is also halves