When light passes through a prism, seven colours namely VIBGYOR are seen on white screen. All these have different angles of deviation. Explain why. Name the colours which suffer maximum and minimum deviation respectively.

Explanation

(i) The phenomenon observed is dispersion of light which means splitting of white light into its constituent colours. It is caused because different constituent colours of light travel with different speeds in the prism and bend through different angles.
(ii) In nature, this pehnomenon is observed in formation of rainbow.
(iii) Based on phenomenon of dispersion, we can conclude that : (a) White light consists of seven colours.
(b) Violet light suffers maximum deviation and red light suffers minimum deviation.