Question

A ray of light passes through an equilateral prism such that the angle of incidence is equal to the angle of emergence and the latter is equal to ${\frac{3}{4}}^{th}$ angle of prism. What will be the deviation?

• A. ${45}^0$
• B. ${37}^0$
• C. ${20}^0$
• D. ${30}^o$

Answer 1

The correct option is D ${30}^o$

$i=\frac{3}{4}A$

Also $i=\frac{A+{\delta }_m}{2}$

$⟹\frac{A+{\delta }_m}{2}=\frac{3}{4}A$

$⟹A+{\delta }_m=1.5A$

0r ${\delta }_m=\frac{A}{2}={30}^o$