Unpolarised light: The light having vibrations of electric field vector in all possible directions perpendicular to the direction of wave propagation is called the ordinary (or unpolarised) light
If unpolarised light falls on a transparent surface of refractive index n at a certain angle ip, called polarising angle, then reflected light is plane polarised with its electric vector perpendicular to the plane of incidence when the refracted and reflected rays make a right angle with each other. Brewster’s law: n = iptan.
