How is polarisation of light obtained by scattering of light?

Explanation

The light from a clear blue portion of the sky shows a rise and fall of intensity when viewed through a polaroid which is rotated. This is because of sunlight, which has changed its direction (having been seattered) on encountering the molecules. Under the influence of the electric field of the incident wave the electrons in the molecules acquire components of motion in both these directions. We have an observer looking at `90^(@)` to the direction on the sun. Clearly, charges accelerating parallel do not radiate energy towards this observer since theier acceleration has no transverse component. The radiation scattered by the molecule is therefore polarized perpendicular to the plane.