(a) Complete the path of the ray until it emerges out of the slab.

(b) In the ray diagram, mark the angle of incidence (i) and the angle of refraction (r) at the first interface. How is the refractive index of glass related to angles i and r?

(c) Mark angle of emergence by the letter e. How are the angles i and e related?

(d) Which two rays are parallel to each other? Name them.

(e) Indicate in the diagram the lateral displacement between the emergent ray and the incident ray. State one factor that affects the lateral displacement.

Solution:

(a) The complete ray diagram of incident ray in glass block is as follows –

(b) The angle of incidence and the angle of refraction are marked as (i) and (r) respectively in part (a).

Therefore, the refractive index of glass is linked to the angles i and r in the following manner –

μ = sin i / sin r

(c) The angle of emergence is marked by (e) in part (a)

The angle of incidence i and the angle of emergence e are related to each other by the relation

∠i = ∠e

(d) Incident and emergent rays are two rays that are parallel to each other.

In the diagram above, XY represents the lateral displacement between the incident and emerging rays.

The lateral displacement is proportional to the thickness of the medium.