Question

A ray of light is incident obliquely from air to glass slab.

1. Draw a labelled diagram showing the change in the path of ray, when it emerges out of glass slab.
2. Name two rays of light which are parallel to each other.
3. Mark the lateral displacement in the above diagram.
4. How are the angle of incidence and angle of emergence related to each other?

Answer 1

(a)

The ray bends towards the normal on entering glass (rarer → denser) and away from the normal on emerging into air (denser → rarer).

(b) The incident ray AO and the emergent ray O’B are parallel to each other.

(c) Lateral displacement is marked as d in the diagram. It is the perpendicular distance between the emergent ray O’B and the incident ray AO produced.

(d) The angle of incidence is equal to the angle of emergence (∠i = ∠e).