When the angle of incidence on a material is $60^{\circ}$ the reflected light is completely polarized. The velocity of the refracted ray inside the material

Question

$\begin{array}{1 1}3 \times 10^8\;m/s \\ \frac{3}{\sqrt 2} \times 10^8m/s \\ \sqrt 3 \times 10^8m/s \\ 0.5 \times 10^8 \end{array} $