Question

what is rayliegh scattering?

Answer 1

the scattering of light by particles in a medium, without change in wavelength.
Rayleigh scattering refers to the scattering of light off of the molecules of the air, and can be extended to scattering from particles up to about a tenth of the wavelength of the light. It is Rayleigh scattering of the molecules of the air which gives us the blue sky.
The air is perfect scatterer agent for blue & violet color. That is the reason why we see sky blue.

hope this will help u.. :-)

Answer 2

According to rayleighs scattering law, scattering is directly proportional to the fourth power of wavelength