Rainbows are a collection of rays that are reflected back from glinting raindrops that are suspended in the atmosphere after a rainstorm. The droplets act as tiny prisms that reflect the light at an angle of approximately 42 degrees. They have a different density than the air that surrounds them. So with each droplet acting as a tiny prism, the light gets broken up into its component wavelengths. Thereafter, it is reflected back at us. This process creates the arc with the band of colours of the spectrum or the rainbow.
Why is the rainbow shaped like an arc?
