Question

A thin glass prism of angle $A={60}^o$ produces an angle of minimum deviation $\mu$ = ${30}^o$. The refractive index of glass is:

• A. 0.5
• B. 1
• C. 1.41
• D. 2

Answer 1

The correct option is C 1.41

Using $\mu =\frac{\sin \left(\frac{A+{\delta }_m}{2}\right)}{\sin \left(\frac{A}{2}\right)}$

Where, $\mu =$Refracive Index

${\delta }_m=$ minimum deviation

$A=$ Angle of prism

$\Rightarrow$ $\mu =\frac{\sin \left(\frac{60+30}{2}\right)}{\sin \left(\frac{60}{2}\right)}$

$\Rightarrow \mu =\frac{\frac{1}{\sqrt{2}}}{\frac{1}{2}}=\sqrt{2}=1.41$

Therefore, c is correct option.