Ans.
1. The band of coloured components of a beam of light is
called a spectrum.
2. The refractive index of the material of the prism is
different for different colours.
3. White light is composed of seven colours. When white
light is incident on a prism, the constituent colours get refracted through
different angles and get dispersed.
4. So, the rays of each colour emerge along different paths
and become distinct. Hence, we get a spectrum of seven different colours.
