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Electric Field and Magnetic Conversion

  1. Jun 15, 2013 #1
    In the solutions of a particular problem, it was stated that:

    <P> = 1/2 |S| = 1/(2μ0) * E^2 / c

    Where <P> is the average power, S is the Poynting vector.

    From the above equation does that mean: B = E /(2μ0c) ?

    I was just wondering how you can show the above relation between Magnetic and Electric field.
     
    Last edited: Jun 15, 2013
  2. jcsd
  3. Jun 15, 2013 #2

    marcusl

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    No it doesn't. The Poynting vector is [tex]\mathbf S=\frac{1}{\mu_0} \mathbf E \times \mathbf B[/tex]
    and, for a wave propagating in free space, B and E are normal to each other (and to the direction of propagation) and have magnitude [itex]B = \frac{1}{c} E[/itex]. Look it up. When you take a time average to get power, it devolves to your first expression.
     
    Last edited: Jun 16, 2013
  4. Jun 16, 2013 #3
    Oh ok, thanks.
     
    Last edited: Jun 16, 2013
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