Using the Fresnel equations, determine Brewster’s angle, the angle of incidence at which no p-polarized light can be reflected (r_∥ → 0). Before polaroid plastic polarizers were invented, polarized light was produced in the lab by using a stack of plates at Brewster’s angle. The partial polarization of light reflected from smooth surfaces is also why polaroid sunglasses work. The sunglasses, which are polarizers, selectively eliminate light reflected from surfaces.