How is rainbow formed?

How many of you have seen rainbow?silly question i guess.you might all have but have you ever wonder how is it formed?let me explain you.

First of all light rays enters into water droplet as water is rarer medium compared to air.light rays bend towards the normal with dispersion. So at first refraction and dispersion happens then after among the several light rays some of the light rays exit from water droplet directly but some suffer total internal reflection which means it gets  reflected back.the after the light ray exit from water droplet to air ie denser to rarer bending away from normal. In this way rainbow is formed.