Question

During dispersion of light through a prism, why do all the colours bend toward the base of the prism?

Answer 1

This is due to the phenomena of refraction of light rays as they travel from one medium to another. As they exit the prism, the rays of light travel from a denser to a rarer medium and thus, the rays bend away from the normal. In this case, the direction of the emergent ray is such that they moves towards the base of the prism.