1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Poynting vector. Conservation theorem.

  1. Aug 19, 2012 #1
    I'm doing a problem where I have to calculate the electric and magnetic fields. I've found B=0, so S=ExB=0. Has it got any meaning?

    Then I calculate the energy density e=E^2 + B^2 = E^2. And finally I have to verify the conservation theorem grad(S)+de/dt=0 for points out of the particle's trayectory. I do this part but the conservation theorem is not satisfied. What is the significance of "out of the particle's trayectory"? Or maybe I've got wrong expressions for E and B...

    Thanks.
     
  2. jcsd
  3. Aug 19, 2012 #2

    mfb

    User Avatar
    2016 Award

    Staff: Mentor

    Your field is static and does not transfer energy.

    You can assume that there are no charges in the (infinitesimal) volume where you verify the relation.
     
  4. Aug 19, 2012 #3
    So, when I do the time derivative of the energy density it must be zero. Then, I think I haven't got the correct expressions for the fields.

    Thanks a lot for your help!
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Poynting vector. Conservation theorem.
  1. Poynting vector (Replies: 2)

  2. Poynting theorem (Replies: 2)

  3. Poynting theorem (Replies: 3)

  4. Poynting vector (Replies: 2)

Loading...