Question

A plane wavefront travelling in a straight line in a vacuum encounters a medium of refractive index $\mu$. At $P$, the shape of the wavefront is :

• A.
• B.
• C.
• D.

Answer 1

The correct option is B

Velocity of the wave in medium $\left(\mu \right)$ is less than that in air. Therefore, wavefront passing through air, reaches a point $\text{P}$ earlier than the ray passing through the medium.

Hence, option $\left(\text{B}\right)$ is the correct shape of the wavefront.