If i see a reflection on a horizontal surface and i try to cancel it out using my polarized sunglasses, then it cancels out much of that reflection. But when i put a small mirror inside that reflection on the same surface and try to cancel out the reflection from that surface using polarized sunglasses, then it cancels out much of that reflection, but it do NOT cancel out the light that is reflected from the surface of the mirror. Why is that?
Please refer the image linked below, if you can not understand what i am describing
Best Answer
Polarization results when unpolarized light impinges on a transparent medium at (or near) Brewster's angle :
A mirror (electrically conducting surface) reflects both polarizations equally.
Your "horizontal surface" may be something like smooth "shiny" "black" plastic, but if it is "black" then why does it reflect at all? Because it is a dielectric material with an index of refraction different from air that has light absorbing particles in it. On the scale of a few light wavelengths it acts like a transparent medium.