Question

A ray of light is incident at an angle of ${60}^{\circ }$ on one face of a prism of angle ${30}^{\circ }$. The emergent ray of light makes an angle of ${30}^{\circ }$ with incident ray. The angle made by the emergent ray with second face of prism will be:

• A. ${30}^{\circ }$
• B. ${90}^{\circ }$
• C. $0^{\circ }$
• D. ${45}^{\circ }$

Answer 1

The correct option is B ${90}^{\circ }$

Here, $i_1={60}^o$

$A={30}^o$

$\delta ={30}^o$

Since, $\delta =i_1+i_2-A$

${30}^{=}{60}^o+i_2-{30}^o$

$i_2=0$

So from the surface, it will make ${90}^o$.