What should be the value of angle $\theta$ so that light entering normally through the surface AC of a prism of refractive index $(n= \large\frac{3}{2})$ does not cross the second refracting surface AB.

Question

 

$(a)\;\theta= \cos^{-1} \frac{2}{3} \\ (b)\;\theta < \cos ^{-1} \frac{2}{3} \\ (c)\;\theta > \cos ^{-1} \frac{2}{3} \\ (d)\; None$