dispersion of light

What do you mean by dispersion of light ? What is a spectrum of light? Name the different colours of light in the proper sequence in the spectrum of white light. OR What do you mean by dispersion ? Name the different colours of light in the proper sequence in the spectrum of white light.

Assertion : Dispersion of light occurs because velocity of light in a material depends upon its colour. Reason : The dispersive power depends only upon the material of the prism, not upon the refracting angle of the prism

Which of the following diagrams shows correctly the dispersion of white light by a prism ?