Question

What is the cause of dispersion of light

Answer 1

Cause of dispersion: Different colours of white light have different wavelengths. The wavelength of violet light is smaller than that of red light. The refractive index of a material in terms of the wavelength of the light is given by Cauchy’s expression.

`mu=a+b/lambda^2+c/lambda^4`

Here, a, b and c are constants for the material.

Thus, a material offers different refractive indices to lights of different wavelengths. This is the cause of dispersion of light