Polarisation by reflection occurs when the angle of incidence is the Brewster’s angle i.e

tan θ_{B}=n_{2}/n_{1} where n_{2}<n_{1}.

When light travels in such a medium the critical angle is sin θ_{c}=n_{2}/n_{1 }

where n_{2} < n_{1}.

As |tan θ_{B}|>|sin θ_{c}|for large angles, θ_{B} <θ_{C} .

Thus, polarisation by reflection shall definitely occur.