Rainbow is formed due to a combination of

(a) Dispersion and total internal reflection

(b) Refraction and absorption

(c) Dispersion and focussing

(d) Refraction and scattering

(a)

Rainbow is formed due to combination of total internal reflection and dispersion.

 

A rainbow is always formed in a direction opp to sun . The water droplets act like small prisms . They refract and disperse the incident sunlight ,then refract it internally and finally refract it against when it comes out of rainbow .Due to the dispersion af light and internal refraction ,different colours reach the observer`s eye