Question

why do we see Rainbow after a rainfall

Answer 1

because the rainbows in some cases see in your eyes because the rainbow make a presence of sunlight in environment and the rainbow make complete 360° in envirinment...
manu rain drops combine with sunlight rays in such cases the sun and rain ☔at one time so the rains combine with sunlight rays so you see a rainbow in the envirinment..
thanks please markbrainlist answer thanks......

Answer 2

We see rainbow after rainfall only when the sun is behind us . The sunrays will refract through the droplets i.e. it will bend as it will enter the droplets and a spectrum of seven colours that is VIBGYOR (violet, indigo,blue,green,yellow,orange and red) will form . Like this infinite number of droplets will form the spectrum of these seven colours and a big rainbow is formed. In simple words , raindrops act as a prism as when light is passed through it , it also creates a spectrum of 7 colours.