What is dispersion?

Explanation

(i) The process of separation of light into its component colours while passing through a medium is called dispersion of light.
(ii) Refractive index of a medium is different for different colours.
(iii) When whit light enters a single medium like glass, the angles of refraction are different for different colours.
(iv) When white light from the sun through air, enters any refracting medium, it emerges as a spectrum of seven colours.
Sir Issac Newton was the first person to use a glass prism to obtain sun's spectrum.