Polarisation by reflection occurs when the angle of incidence is the Brewster’s angle i.e
tan θB=n2/n1 where n2<n1.
When light travels in such a medium the critical angle is sin θc=n2/n1
where n2 < n1.
As |tan θB|>|sin θc|for large angles, θB <θC .
Thus, polarisation by reflection shall definitely occur.