A water film is formed on a glass-block. A light ray is incident on water film from air at an angle $60^{\circ}$ with the normal. The angle of incidence on glass slabs is $ \bigg[ \: given\: \mu_g = 1.5,\: \mu_W = \large\frac{4}{3} \bigg] $ :

Question

$\begin {array} {1 1} (1)\;sin^{-1} \bigg( \large\frac{1}{\sqrt 3} \bigg) & \quad (2)\;sin^{-1} \bigg( \large\frac{4\sqrt 3}{9} \bigg) \\ (3)\;sin^{-1} \bigg( \large\frac{9\sqrt 3}{16} \bigg) & \quad (4)\;sin^{-1} \bigg( \large\frac{3\sqrt 3}{8} \bigg) \end {array}$