What is an unpolarized light ? Explain with the help of suitable ray daigram how an unpolarized light can be polarized by reflection from a transparent medium. Write the expression for Brewster angle in terms of the refractive index of denser medium.

Explanation

In an unpolarised light the vibrations of electric field vector are in every plane perpendicular to the direction of propagation of light.
When unpolarised light is incident on the boundary between two transparent media, the reflected light is 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 angle `mu=tani_(B)`