State: (a) the difference between plane polarized light and ordinary light; (b) two uses of polaroids.

Answer Details

(a) Difference between plane polarized light and ordinary light: In ordinary (unpolarized) light the vibrations of the electric field take place in all directions (all planes) perpendicular to the direction of propagation. In plane polarized light the vibrations are restricted to a single plane containing the direction of propagation.

(b) Two uses of polaroids:

1. In polaroid sunglasses, to reduce glare from light reflected off surfaces such as water and roads.
2. In the control of light intensity and in photography (polarizing filters), and in liquid-crystal displays (LCDs) and stress analysis of transparent materials.