What is Brewster’s angle? Derive relation between Brewster angle and refractive index of medium which produces Plane Polarized light.

Brewster’s angle, or the polarizing angle, is defined as an angle at which an incident beam of unpolarized light is reflected after complete polarization. The reflected light at the polarizing angle is linearly polarized by having its electric field vectors parallel to the plane of reflecting surface and perpendicular to the plane of incidence. The reflected light is partially polarized at other angles.

Brewster’s angle can be calculated using the following equation:

Where n is the refractive index of the medium of light reflection, q_i is the angle of incidence, and q_r is the angle of refraction.