Answer: As per the question, a ray of light is incident on a surface and it is partly reflected and refracted. The incident light is an unpolarised light. The reflected light is partially polarised.
If the angle of incidence becomes equal to the Brester angle (polarising angle), then the reflected light is completely plane polarised.
The incident ray is a ray that hits the surface of the water. A reflected ray will always correspond to the incident ray and it is the light that is reflected by the surface of the water. Meaning, all rays that hit are incident rays, however, some are reflected rays.
