Question

What is the direction (vertical or horizontal) of the transmission axis of Polaroid sunglasses? Give the physical reason for your answer.

Answer 1

Polaroid filters are incorporated into sunglasses. Because the light reflecting off most surfaces will tend to be partly polarized with a predominance of the electric fields oscillating horizontally, that “glare” can be diminished by having the transmission axis of the Polaroid filters aligned vertically.
http://www.physics.uc.edu/~sitko/LightColor/16-Polarization/polarization.htm