Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Faraday's Principal of induction

  1. Oct 3, 2004 #1
    Okay, I've been told that the E and B fields in photons are out of phase, I've been told that they are in-phase.
    If you just look at Faraday's Principal of induction, it follows that they are out of phase, but I've been told that when they are propogating they are not.
    Why the difference? How should a system of four equations have another answer that the induction law does not allow?

  2. jcsd
  3. Oct 3, 2004 #2
    As I remember, the E and B fields of plane electromagnetic waves are perpendicular to each other and perpendicular to the direction of propagation. I'm not sure you can talk about in phase and out of phase in these conditions. Their mins and maxes do occur at the same point along the direction of propagation.
  4. Oct 3, 2004 #3
    Yes, but why?
  5. Oct 3, 2004 #4


    User Avatar
    Science Advisor

    This is pretty basic stuff, covered in most intermediate and advanced texts on E&M. It is all about solving the Maxwell Eqs with plane waves. Because of the transverse nature of the waves, there are two spatially independent solutions given any propegation direction. E and B are temporarally in phase, and 90 degrees out of phase spatially. All of this is subsumed under the concept of polarization -- worth reading about.

    Reilly Atkinson
  6. Oct 3, 2004 #5
    Hehe, I posted a question about this a couple of months ago and it turned into a rather involved thread. And I never really felt as though I had a satisfactory picture of it... but the way reilly just phrased it is a good explanation and sheds a lot of light on the matter :biggrin:
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Faraday's Principal of induction
  1. Uncertainty principe (Replies: 1)