Which of the following is not a reason behind rainbow formation?
absorption
Rainbow is formed when sunlight is dispersed by rain droplets which are suspended in air. When sunlight enters the raindrop it refracts then it undergoes total internal reflection from the rear end of the droplet surface and again refracted out in the atmosphere and that's how we see a rainbow. So all the given process i.e total internal reflection, refraction, and dispersion take place in the rainbow formation. Absorption of light doesn't takes place in the process of formation of a rainbow.