Question

In Fig, $PQ$ and $PR$ are the two light rays emerging from an object $P$. The ray $PQ$ is refracted as $QS$. Name the phenomenon that occurs if the angle of incidence $\angle PQN$ is increased :

• A. Refraction
• B. Total internal reflection
• C. Minimum deviation
• D. None of these

Answer 1

The correct option is B Total internal reflection

Critical angle is the angle of incidence for which angle of refraction is ${90}^o$ i.e. $\angle PQN$. If the angle of incidence is increased greater than critical angle, it will undergo total internal reflection.