In 1812 Brewster found that for an incident, unpolarized beam of light the maximum polarization of the reflected light beam is achieved when the transmitted beam and the reflected beam make an angle of 900. When unpolarized light reflects off of a nonconducting surface, it is partially polarized parallel to the plane of the reflective surface. There is a specific angle of incidence relative to that plane called Brewster's angle at which the light is 100% polarized. This occurs when the angle between the reflected ray and the refracted ray is 90o.
At what incident angle is sunlight reflected fully plane-polarized from a lake? What is the refraction angle?