Question

Upward rays of light in water toward the water-air boundary at angles greater than 48 degreees to the normal are totally reflected. No rays beyond 48 degrees refract outside. How about the reverse? Is there an angle at which light rays in air meeting the air-water boundary will totally reflect? Or will some light be refracted at all angles?

Answer 1

Some light is reflected at all angles, for unpolarized light coming from air or vacuum to a higher-index medium such as water. However, for light of a certain linear polarization, there is no reflection at one particular angle angle of incidence, called Brewster's angle.