Question

A ray of light is incident on a medium at $\angle 60°$. The angle of refraction is different for different media for an angle of incidence = 60°.

In which medium the speed of light is slowest?

• A. 1
• B. 2
• C. 3
• D. same in all

Answer 1

The correct option is C

3

The angles of refraction for the different media are:
Medium 1 = $\angle 60°$, medium 2 = $\angle 45°$, medium 3 = $\angle 30°$.

As we know, light while entering a denser medium from a rarer medium, gets slowed down which is why bends towards the normal and vice-versa.
So, using this concept, the densest medium is medium 3 as light bends by the maximum amount in medium 3.
Therefore speed of light is minimum in medium 3.