Question

The wavefront at t=0 has moved to form the wavefront at t=t. The points C and D are a result of wavelets from:

• A. A and B respectively
• B. B and A respectively
• C. No points on wavefront at t=0
• D. All points on wavefront at t=0

Answer 1

The correct option is D

All points on wavefront at t=0

You might be tempted to think that C comes from A and D from B, but, its not like that my friend, Huygens's principle states that ALL the points are giving secondary wavelets and the new wavefront is an envelope of all of them, note that there is no one to one matching between points from one wavefront to the subsequent other.