CBSE Class 12-science Answered

When a beam of white light is passed through a medium containing particles whose size is of the order of wavelength of light, then the beam gets scattered. When the scattered light is seen in a direction perpendicular to the direction of incidence, it is found to be plane polarised .This phenomenon is called polarisation by scattering.

The sunlight is ordinary unpolarised light. However, when the sunlight is scattered on encountering the molecules of earth’s atmosphere, for an observer looking at sunlight in a direction making 90⁰ to the direction of incident sun rays,the scattered light is found to be plane polarized.Light scattered in a direction perpendicular to the incident light is always plane polarised.