Question

What is "dispersion of white light"? Draw a labelled diagram to illustrate the recombination of the spectrum of white light. Why is it essential that the two prisms used for this purpose should be identical and placed in an inverted position with respect to each other?

Answer 1

The phenomenon of splitting of white light into its constituent colours on passing through a prism is known as the dispersion of white light. This splitting of the light rays occurs because different colours of light bend through different angles with respect to the incident ray, as they pass through a prism.


It is essential that the two prisms used for the purpose should be identical and placed in an inverted position with respect each other so that the second prism completely nullifies the dispersion caused by the first prism and we get pure white light.