Why do small particles only scatter shorter wavelength (blue light) and why do big particles scatters red light????And why does bigger air particles absorb all 7 colours and appears it in white light?????explain in brief.......plz

Dear Student.
Why do small particles only scatter shorter wavelength (blue light) and why do big particles scatters red light????
This statement is wrong as  small particles like air molecules scatters blue light more than red.  Big particles such as dust or water molecule scatters light such that it appears white only, that is all colours are scattered in same way.

The blue component of the spectrum of visible light has shorter wavelengths and higher frequencies than the red component.


Thus, as sunlight of all colours passes through air, the blue part causes charged particles to oscillate faster than does the red part.
The acceleration of the charged particles is proportional to the square of the frequency, and the intensity of scattered light is proportional to the square of this acceleration. Scattered light intensity is therefore proportional to the fourth power of frequency.

The faster the oscillation, the more scattered light is produced, so blue is scattered more strongly than red.
Now question arise why after scattering from big particles light appears to be white, it is because big particles like dust particle or water molecules are larger than wavelength of light and hence scattering for all colour wavelength is not much large so we see light as white light only.

Regards

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