When does a ray passing through a prism deviate away from the base of the prism ?

When does ray incident on a prism deviate away from the base?

Explain how a ray of light passing through a prism is deviated towards the base of the prism.

For a light ray passing through a prism

In the diagram the ray passing through prism is parallel to the base. Refractive index of material of prism is

Why does a ray of light while passing through a prism, bend towards its base?

The angle of minimum deviation of a ray passing through a prism is the minimum for