Question

According to Huygens principle, a wave front propagates through a medium by

• A. pushing particles of the medium
• B. propagating through medium with speed of light
• C. carrying particles of same phase along with it
• D. creating secondary wavelets which forms a new wave front

Hint:

Every point on a wavefront acts as a source of secondary wavelets.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept
Huygens principle explains how a wavefront moves forward in a medium without any particles travelling along with it.

Step 2: Statement of the Principle
Every point on a wavefront behaves as a new source of secondary wavelets.
These wavelets spread with the speed of the wave in that medium.

Step 3: New Wavefront
The forward envelope (common tangent) of all the secondary wavelets gives the new wavefront at a later time.

Step 4: Compare the options
Only option (D) describes the creation of secondary wavelets forming a new wavefront.

Final Answer:
A wavefront advances by creating secondary wavelets that form the new wavefront. \[ \boxed{\text{(D) }\text{creating secondary wavelets which forms a new wave front}} \]