In your laboratory you trace the path of light rays through a glass slab for different values of angle of incidence (∠i) and in each case measure the values of the corresponding angle of refraction (∠r) and angle of emergence (∠e). On the basis of your observations your correct conclusion is :

When a ray of light enters from air (an optically rarer medium) to glass (an optically denser medium), it bends towards the normal. Therefore, the angle of refraction ($\angle r$) is less than the angle of incidence ($\angle i$), which means $\angle i > \angle r$.

When the light ray emerges from the opposite parallel face of the rectangular glass slab into air, it bends away from the normal. Since the two refracting surfaces are parallel, the emergent ray is parallel to the incident ray, meaning the angle of emergence ($\angle e$) is equal to the angle of incidence ($\angle i$), i.e., $\angle i \approx \angle e$.

• Option (a) is correct because it accurately states that $\angle i > \angle r$ and $\angle i \approx \angle e$.
• Option (b) is incorrect because $\angle i$ is greater than $\angle r$, not less.
• Option (c) is incorrect because $\angle i$ is nearly equal to $\angle e$, not greater, and $\angle i$ is not equal to $\angle r$.
• Option (d) is incorrect because $\angle i$ is nearly equal to $\angle e$, not less, and $\angle i$ is not equal to $\angle r$.