Question

In the fig., PO is a ray of light incident on a rectangular glass block.
(a)   Complete the path of the ray through the block.
(b)  In the 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 the 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.

Answer 1

(a) Diagram showing complete path of light : 

(b) Angle of incidence and angle of refraction marked in the above diagram.

R.I = `"sin i"/"sin r"`

(c) Angle of emergence is marked in the above diagram.

Angle of incidence = Angle of emergence

(d) Rays IO and O'E are parallel to each other. These are incident and emergent rays respectively.

(e) In the diagram above, the lateral displacement is indicated by XY.