Question

What is the angle of deviation in a glass slab?

Answer 1

Light is deflected as it enters a material with refractive index > 1. A ray of light is deflected twice in a prism. The sum of these deflections is the deviation angle. When the entrance and exit angles are equal, the deviation angle of a ray passing through a prism will be a minimum.

Answer 2

Answer:

difference in angle of incidence and that of refraction

Explanation:

When a light ray passes to a medium with a different density, it deviates. Similarly, when it leaves the medium, it deviates again.

The sum of the deviations is the angle of deviation.

i.e. difference in incidence and refraction.