When unpolarized light of certain wavelength is incident upon the surface of a transparent substance it experiences maximum plane polarization at the angle of incidence whose tangent is the refractive index of the substance.
The specific value of angle of incidence at which the reflected light is completely polarised is called as the polarising angle
µ= Refractive index of the medium
ip = polarizing angle
Problem 1: A certain polarizer has a refractive index of 1.33. Find the polarization angle and angle of refraction?
Refractive index of the polarizer = 1.33
The Brewster’s law is μ = tan ip
ip = tan−1 (1.33)
ip = 53.06
Now, Angle of refraction
It is given that ip + ir = 90 degrees
Thus, angle of refraction or ir = 90 – 53.06
Angle of refraction = 36.94