Figure P 22.59 shows the path of a beam of light through seyeral layers with different indices of refraction. (a) If $\theta_{1}=30.0^{\circ}$ , what is the angle $\theta_{2}$ of the emerging beam? (b) What must the incident angle $\theta_{1}$ be to have total internal reflection at the surface between the medium with $n=1.20$ and the medium with $n=1.00 ?$