Previous: Total internal reflection
Another aspect of light that is quite common is the breaking up of
white light into its constituent colours. For example, if a beam of
white light enters a glass prism, as shown in the Figure below, what
from the other side is a spread out beam of many coloured
Dispersion of white light by a prism
The explanation for this phenomenon is simple: the white light
consists of literally all the colours in the rainbow. The various
colours are refracted through different angles by the glass, and are
``dispersed'', or spread out. From the figure, we see that blue light
gets bent more by the glass than red light.
The triangular shape of the prism is
designed to maximize this effect.