Question

Which of the following is the best experimental set-up out of the four shown for tracing the path of a ray of light passing through a rectangular glass slab ?

Answer 1

For the given experiment, the best set-up is that in which the light is incident at an angle of around 45° with the normal. In this set-up, deviation of rays are clearly observed and the lateral displacement can be correctly measured. In the experimental set-up shown in figure B, the angle of incident light with the normal appears to be around 45°.
Hence, the correct option is B.