Lag1989 problem number 22.10

A beam of light passes through a liquid poured into a glass vessel (n=1.5) and is reflected from the bottom. The reflected beam is completely polarized when it falls on the bottom of the vessel at an angle of 42°37´. Find: a) at what angle should a light beam fall on the bottom of the vessel in order for total internal reflection to occur; b) refractive index of the liquid.