Statement - I :When an unpolarised light is incident on a glass plate at Brewster angle, the reflected ray and refracted ray are mutually perpendicular
Statement - II :The refractive index of glass is equal to sine of the angle of polarisation.

Brewster's law:
When an unpolarized light is incident on a glass plate at Brewster angle, the reflected ray becomes plane polarized and the refracted ray is partially polarized also the reflected and refracted ray are mutually perpendicular.

Also, =tan${\mathrm{i}}_{\mathrm{p}}$ Where, μ=refractive index of medium ${\mathrm{i}}_{\mathrm{p}}$= Brewster angle.

Relflected and refracted are always perpendicular to each other.