A student traces the path of a ray of light through a rectangular glass slab for different values of the angle of incidence. He observes all possible precautions at each step of the experiment. At the end of the experiment, on analyzing the measurements, which of the following conclusions is he likely to draw?

As the incident ray is parallel to the emergent ray, thus the incidence angle is equal to the emergence angle i.e., ∠i=∠e. Also, the ray traveling from a rarer medium (air) to a denser medium (glass slab) slightly bends towards the normal after refraction, thus the angle of refraction is smaller than the angle of incidence i.e., ∠r<∠i ⇒ ∠i=∠e>∠r