Concept:Rainbow formation is caused by the dispersion of white sunlight into its component colours by tiny water droplets suspended in the atmosphere after rainfall.
Explanation:White light from the Sun is a mixture of different colours, each having a different wavelength.
When sunlight passes through raindrops, each droplet acts like a tiny prism.
The raindrops refract and reflect the light inside them, causing the white light to split into its constituent colours.
This splitting of white light into a spectrum of colours is called dispersion.
Dispersion occurs because different colours of light bend by different amounts when they enter and leave the water droplets.
The colours appear in a specific order: red at the outer edge and violet at the inner edge.
Rainbows are visible only when the observer stands with the Sun behind them and looks at the rain in front.
Therefore, a rainbow is seen after rainfall when the sky is still filled with water droplets and sunlight is available.
Answer:The correct option is D: white light is dispersed into its constituent colours after rainfall.