A ray of light incident at an angle $\theta$ on an refracting face of a prism emerge from the other face normally . If the angle of the prism is 5 and the prism is made of a material of refractive index 1.5 , the angle of incident is

Question

$\begin{array}{1 1} 7.5^{\circ} \\ 5^{\circ} \\ 15^{\circ} \\ 2.5^{\circ} \end{array}$