Show using a proper diagram how unpolarised light can be linearly polarised by reflection from a transparent glass surface.

Explanation

Plane polarised light can be obtained by reflection from a transparent surface (say a plane glass plate) when the light is incident on the surface at the polarising angle `i_(p)`, Value of polarising angle is given by Brewster.s law, according to which
`tani_(p)=n or i_(p)=tan^(-1)(n)`
In such a condition, the reflected light contains vibrations of electric vector perpendicular to the plane of incidence only and is thus, completely plane polarised one.