Question

What is phase difference?

Answer 1

When there is a phase difference between 2 waves that have the same frequency and wavelength, there is a time difference between when the peaks and valleys occur for the 2 waves.

Explanation:

The answer I gave above is probably fairly equivalent to what you were told in your book or class. I found a demonstration that I hope will help. Go to the site

and start the video.

The demonstration that I think might help (5 colored waves) starts at about t=4:30. The earlier parts may, in general, help your understanding of waves.

I hope this helps,
Steve