WAEC - Physics (2001 - No. 27)
Dispersion of white light by a glass prism occurs because
white light consist of a mixture of seven different colour
the refractive index of glass is different from each constituent colour of white light
the speed of each colour of light in the glass is proportional to the refractive index of glass for each colour
the speed of each colour of light in the glass is proportional to the angle of refraction in he prism
Maelezo
Dispersion of white light by a glass prism occurs because the refractive index of glass varies for each color. This difference causes each color to bend at a different angle, resulting in a spectrum of colors.