how does rainbow form?
Rainbow forms when sunlight hits the water droplets suspended in the atmosphere and undergoes total internal reflection. When the sunlight comes out of the drop it disperses, where the drop acts like a small prism. This dispersion or breaking up of light into several colors is what forms the Rainbow.
rainbows are beautiful and appear after rain. It is a mixture of refraction and reflection and both phenomena must occur at the same time. Refraction occurs when light moves from one substance to another, and rays of color bend at the same time. Sunlight enters a raindrop and breaks into different colors that move in slightly different directions, the light refracts and is reflected off the back of the raindrop. When it passes back through the air again it is further refracted and causes the rainbow to appear.