The phenomenon of restriction of vibrating of light waves in particular plane is called polarization of light and such light is called plane polarized light.
The plane in which polarized light vibrates is called plane of vibration. If the fig ABCD is the plane of vibration.
The plane perpendicular to the plane of vibration is called plane of polarization. In the figure EFGH is the plane of polarization.
Polarization by reflection:
The light reflected from the transparent medium is partially polarized. If reflecting the angle of incidence changed surface the degree of polarization of reflected light also changes. At particular angle of the incidence the reflected light is completely plane polarized.
The degree of incidence at which the reflected light become completely plane polarized called angle of polarization (θp).