Why is the reflected light partially polarized when a beam of non-polarized is incident from air on a surface?

When non-polarized light strikes a surface, such as water or glass, some of the light is reflected while some is refracted. The reflected light undergoes a change in polarization due to the interaction with the surface, where the electric field vectors of the light waves are preferentially oriented in a particular direction. This phenomenon is more pronounced at certain angles, notably Brewster's angle, where the reflected light becomes maximally polarized. As a result, the reflected beam is partially polarized, with a higher concentration of electric field vectors aligned perpendicular to the direction of reflection.