A beam of unpolarized light is incident on an air-glass interface derive, using a suitable ray diagram that light reflected from the interface is completely polarised, when
Step 1: Given data
When unpolarized light is incident on a transparent refracting medium, at a particular angle of incidence the reflected light and refracted light are perpendicular to each other that angle of incident is known as a polarizing angle.
The reflected light is completely plane polarised.
Let be the polarising angle.
Let be the angle of refraction.
Let the refractive index of air be .
Let the refractive index of glass be .
Therefore, the reflected ray and refracted ray are perpendicular to each other.
Step 2: Formula Used
According to Brewster’s law,
According to Snell’s law
Step 3: Brewster's Angle
Upon substituting the values we get,
This relation is known as the Brewster angle.