Question

In the diagram below, PQ is a ray of light incident on a rectangular glass block.

 (i) Copy the diagram and complete the path of the ray of light through the glass block. In your diagram, mark the angle of incidence by letter ‘i’ and the angle of emergence by the letter ‘e’. 

(ii) How are the angles ‘i’ and ‘e’ related to each other?

Answer 1

(i)

(ii) When the incident ray is undergoing minimum deviation the angle of incidence is equal to angle of emergence, i.e., ∠i – ∠e