Question

What happens to light when it gets dispersed? Give an example.

Answer 1

Dispersion is the splitting of white light when it passes through a prism. The colorful band of light obtained after dispersion is called the spectrum. Dispersion is responsible for the rainbow that forms in the sky. The main cause of dispersion is the difference in the speed of colors present in white light.

Complete step by step solution:
Dispersion is the splitting of white light when it passes through a prism. White light enters the prism, gets refracted on the side through which it enters. Then it travels a straight line path and again gets refracted since the medium gets changed again. Since there are two successive refractions of the same measure, the colours deviate and we obtain a band of colors instead of a beam of light.
The main cause of dispersion is the difference in the speed of colors present in white light.
Red gets the least deviated amongst all the colors since its wavelength is more and violet gets the most deviated since its wavelength is less. Thus, we find violet at the lowest end of the spectrum and red at the highest end of the spectrum.
An example of the natural phenomenon is the rainbow formation which takes place on similar lines. The small suspended water droplets act as small prisms and disperse white light into its constituent colors.

Note: The order of the colors found in the spectrum is given as VIBGYOR where V is violet, I is indigo, B is blue, G is green, Y is yellow, O is orange and R is red. In a rainbow the colors at the lower end are not clearly distinguishable since they have shorter wavelengths which are almost similar so the difference in deviation is not very large. Hence the boundaries are not clearly visible.