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!

Electromagnetic waves

  1. May 12, 2012 #1
    I was just thinking about electromagnetic fields and magnetostatics. Magnetostatics is the study of magnetic fields where they do not change or very little. I was wondering if a static magnetic field is still considered part of a Electromagnetic field? Since the magnetic field is not changing, then there should be no electric field.

    However a thought did occur which is that even though the magnetic field may be steady, in reality it can never be in perfect steady state because there is still small changes in the currents and even in the material which created it which cause a change. Even if the changes are over the lifetime of the universe, that is still considered a change, very small but still a change. So from this I assume that there is no such thing as a magnetic field with out a electric field. It is just that in say a bar magnet which does not seem to change, the electric component of the electromagnetic field is very small because there is very little change in the magnetic field.

    Is the right? That there is and can never be magnetic field without a electric field.

    It seems to make perfect since now, especially since I read and hear they are both the same thing and create each other but now I think I actually understand it since I started trying to model it in my head. The problem I use to have was how was a magnetic field from a electromagnet can somehow become a electromagnetic field and the answer is it never did, it was always part of it because it always had an electric component.
    Last edited: May 12, 2012
  2. jcsd
  3. May 13, 2012 #2


    User Avatar
    Staff Emeritus
    Science Advisor

    The electric and magnetic forces are part of the combined Electromagnetic force. I would say that saying the "EM Field" is perfectly fine overall. If you want to discuss a particular aspect of the field, such as the magnetic field of a magnet, you can simply say "Magnetic Field".

    One thing to remember is that an electric field looks like a magnetic field if you are moving by it or it is changing, and the magnetic field looks like an electric field in the same situation. It simply depends on your frame of reference. They are both part of the Electromagnetic field, with each part seen under different conditions.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook