The light coming from the sun is mainly white light. In the white light, a lot of different colours are mixed. These colours are seen in a rainbow. A rainbow is formed in rainy seasons. Sunlight falling on the rain is deflected twice by the water droplets. When it enters the water droplets it is deflected first. The light is split into its component colours because the blue light with shorter wavelength bends more than the red light with longer wavelength. The split rays travel to the rear wall of the droplet, where they are refracted again when they come out. Thus, the rays form a colourful rainbow!