The Figure Shows a Point Source of Unpolarized Light at a Inside

Multiple Choice

The figure shows a point source of unpolarized light at A inside a uniform transparent crystal. The ray AO in the crystal strikes the plane surface SS' making an angle of 30° with the normal. This angle is the critical angle for transmission into air.

-Determine the index of refraction of the crystal.

A) 0.58
B) 1.2
C) 1.7
D) 2.0
E) 2.4