Question

For a transverse wave, what is a wavefront?

Answer 1

 wavefront is the long edge that moves, for example, the crest or the trough

Answer 2

Explanation:

A wavefront is the long edge that moves, for example, the crest or the trough. Each point on the wavefront emits a semicircular wave that moves at the propagation speed v. These are drawn at a time t later, so that they have moved a distance s = vt.