Question

Select from the following the best set-up for tracing the path of a ray of light through a rectangular glass slab: (1)
(A) I
(B) II
(C) III
(D) IV

Answer 1

The incoming ray of light should not fall perpendicularly on glass slab as the light will emerge straight and refraction will not be traced. So the light ray should not be very close nor to far from the normal as it is difficult to trace the emergent rays. 

(i) is the right answer.