A light ray traveling in air is incident on one face of a right-angle prism of index of refraction $n=1.50$ as shown in Figure $P 35.70$, and the ray follows the path shown in the figure. Assuming $\theta=60.0^{\circ}$ and the base of the prism is mirrored, determine the angle $\phi$ made by the outgoing ray with the normal to the right face of the prism.
(FIGURE CANT COPY)