Purpose:Demonstrate polarization at Brewster's angle.
Description:Light from a bright point source with a condenser lens and iris is incident on a semicircular lucite slab through the curved surface. Using the protractor the Brewster angle is found by rotating the slab until the angle between the refracted ray and the ray internally reflected off the flat surface is 90 degrees. The polaroid in the photograph at the left passes only vertically polarized light. Rotating the polaroid in the incident light so that it passes only horizontally polarized light (lower photograph) verifies that the internally reflected ray is polarized in the vertical plane.