In the figure given below, a narrow beam of white light is shown to pass through a triangular glass prism. After passing through the prism, it produces a spectrum XY on the screen.
(i) The phenomenon is called dispersion.
(ii) X - Violet, Y - Red
(iii) Different colours of white light bend through different angles with respect to the incident beam of light due to difference in speed of light of different wavelengths.