Question

A student traces the path of a ray of light through a rectangular glass slab for the different values of 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?

• A. $\angle i=\angle e<\angle r$
• B. $\angle i<\angle e<\angle r$
• C. $\angle i>\angle e>\angle r$
• D. $\angle i=\angle e>\angle r$

Answer 1

The correct option is D $\angle i=\angle e>\angle r$

As the incident ray is parallel to the emergent ray, thus incidence angle is equal to angle of emergence i.e $\angle i=\angle e$

Also the ray travelling from rarer medium (air) to the denser medium (glass slab) slightly bends towards the normal after refraction, thus angle of refraction is smaller than angle of incidence i.e $\angle r<\angle i$

$⟹$ $\angle i=\angle e>\angle r$