Question

Explain briefly , with the help of a neat labelled diagram, how white light gets dispersed by a prism.

Answer 1

When white light is incident on the first surface of a prism and enters in glass, light of different colors due to different speeds in glass, is refracted or deviated through different angles. Thus the dispersion of white light into its constituent colors takes place at the first surface of prism.

On the second surface, only refraction takes place and different colors are deviated through different angles. As a result, the colors get further separated on refraction at the second surface (violet being deviated the most and red the least).