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If E field points up, which way does B field point?

  1. Apr 14, 2008 #1
    Ok, dumb question, I know. But it's been bugging me, and I can't find a straight answer anywhere, so here it goes:

    In a classical electromagnetic wave, where the electric field points upward, will the magentic field point AT me or AWAY from me?

    I've seen textbooks depict them both ways - can it really be both ways, or is it just sloppyness on the part of the drafters?

    All responses appreciated.
  2. jcsd
  3. Apr 14, 2008 #2


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    Staff: Mentor

    What is the vector definition of the Poynting vector?
  4. Apr 14, 2008 #3
    Ah, I forgot to mention that I'm imagining the electromagnetic wave propagating to our right-hand side. So, I go E cross B with S pointing in the direction of propagation...to answer my own question, the magnetic field must point AT me...and, yes, the opposite depiction in some text books must be a drafting error.

    Thank you, Berkeman
    Last edited: Apr 14, 2008
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