CBSE · Class 10 · Science · The Human Eye and Colourful WorldExplain the phenomenon of dispersion of white light through a glass prism. Draw a labelled diagram or describe the order of colours obtained.

Dispersion of white light is the phenomenon of splitting of a beam of white light into its constituent seven colours when it passes through a transparent glass prism. This band of coloured components of a light beam is called its spectrum. The white light is composed of different wavelengths or frequencies. When light rays enter the prism from air into glass, different colours bend at different angles due to the varying refractive index of glass for different wavelengths. Red light has the longest wavelength and bends the least, whereas violet light has the shortest wavelength and bends the most. Therefore, the colours appear in the specific sequence of VIBGYOR: Violet, Indigo, Blue, Green, Yellow, Orange, and Red. Sir Isaac Newton was the first to use a glass prism to obtain the spectrum of sunlight. He also demonstrated that all these colours can be recombined to form white light by placing an identical inverted prism in the path of the dispersed rays.