Name: Dispersion of White Light
Uploaded: 2019-07-19
Duration: 4 min 56 s
Description: We all love looking at and clicking pictures of rainbows in the sky. But have you ever wondered, how is a rainbow formed? Let's watch this video and understa...

Question

Explain the cause of dispersion

Accepted Answer

When a ray of light is passed through a prism, it suffers deviation. The angle of deviation of a ray of light depends upon the wavelength or colour of light.
According to Cauchy, the refractive index of a material depends upon the wavelength of light used and is given by
$μ = a + \frac{b}{λ^{2}} + . . . .$
where,a, b etc. are constants for the material.
Light consists of seven colours. Out of the seven colours of the spectrum, the wavelength of violet light is minimum and of the red colour is maximum. Therefore, using Cauchy formula, the refractive index of the material of the prism for violet colour is maximum and the refractive index for the red ray is minimum.

Therefore, the light of different colours are deviated at different angles when they emerge out of the prism and we get the dispersion of light.

Explain the cause of dispersion

Important Questions on Dispersion and Scattering of Light

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