Question

Splitting up of white light into the seven colours is known as
A. Reflection
B. Refraction
C. Interference
D. Dispersion

Answer 1

Hint: Dispersion of white light is explained as the splitting up of white light into seven constituent colours when it is passed through the prism. White light dispersion is happening because that as they pass through a prism, the different colours of the light will bend at various angles with respect to the incident ray on the prism.

Complete step by step answer:
First of all let us check what dispersion actually means. Dispersion of white light is explained as the splitting up of white light into seven constituent colours when it gets passed through the prism. Dispersion is occurring on the basis of refraction and Snell's law. White light in appearance white because it consists of every colour of the visible spectrum. Even though they are very nearer, the index of refraction for each colour is specific in non-vacuous materials. These unique indices result in differing wavelengths to follow a different path. White light gets into a prism on the left, then is dispersed in accordance with the wavelength into a rainbow pattern. Since violet light is having a shortest wavelength, it is getting slowed more than the longest wavelengths of red light. Therefore the violet light is bent into the most and red light will bend to the least. This separation of white light into its constituent seven colours is called dispersion of light. Therefore the correct answer is option D.

Note:
As light passes from air into the glass with different refractive index, there is reduction in velocity. Due to the longer wavelengths, red waves can travel faster and it is refracted the least. But in the case of violet waves can travel the slowest and are refracted the most.