When angle of incidence is equal to Brewster's angle,he transmitted light is unpolarised and reflected light is plane polarised.
Consider the diagram in which unpolarised light is represented by dot and plane polarised light is represented by arrows.
Polarisation by reflection occurs when the angle of incidence is the Brewster's angle
i.e, `tan i_(B)=""^(1)mu_(2)=(mu_(2))/(mu_(1))` where `mu_(2) lt mu_(1)`
when the light rays travels in such a medium, the critical angle is
`Sin i_(C)=(mu_(1))/(mu_(2))`
where `mu_(2) lt mu_(1)`
As `|tan i_(B) | gt |Sin i_(C)|` for large angles `i_(B) lt i_(C)`
Thus, the polarisation by reflection occurs definitely.
