Question

The refractive index of a prism is 2. This prism can have A mximum refracting angle of

• A. ${90}^{\circ }$
• B. ${60}^{\circ }$
• C. ${45}^{\circ }$
• D. ${30}^{\circ }$

Answer 1

The correct option is B ${60}^{\circ }$

Critical angle ${\theta }_C=si{n}^{–1}\left(\frac{1}{\mu }\right)$
$=si{n}^{–1}\left(\frac{1}{2}\right)={30}^{\circ }$
If $A>2{\theta }_C$ the ray does not emerge from the prism. So, maximum refracting angle can be ${60}^{\circ }$.