1. PF Contest - Win "Conquering the Physics GRE" book! Click Here to Enter
    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!

Electric and magnetic fields

  1. Sep 22, 2009 #1
    1. The problem statement, all variables and given/known data


    My professor offered the following question: Is it possible to have an electromagnetic field that appears as a purely electric field in one inertial frame and as a purely magnetic field in some other inertial frame?

    2. Relevant equations

    3. The attempt at a solution

    I agree that if there is a point charge at rest there exists only electric field lines. And I also agree that if the charge is put in motion that from the frame of the lab there is an electric and magnetic field but from a frame attached to the charge there is only an electric field. But I can't convince myself there could be one frame where there is only an electric field and another frame in which there is only a magnetic field. Can someone point me in the direction of what I am missing? Is this a qualitative or quantitative issue? Am I oversimplifying this?

    Thanks in advance!
  2. jcsd
  3. Sep 23, 2009 #2


    User Avatar
    Science Advisor
    Homework Helper

    Hi Starproj! :smile:

    Hint: what invariants do you know involving E and B? :wink:
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook