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How can the unit of H and J be different?

  1. Feb 7, 2015 #1
    Maxwell's equation is

    ∇×H=J + ...

    but the unit of H is A/m while J's unit is A/m2

    as quoted from wikipedia

    how can it be possible?
  2. jcsd
  3. Feb 7, 2015 #2


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    Science Advisor

    You're taking the derivative of H, and this involves dividing by a length. The components of Curl(H) has terms like partial(H)/partial(x), so there is an additional length in the denominator. This is just like the fact that the units of velocity are m/s, while the units of acceleration (which is the time derivative of velocity) are m/s^2.
  4. Feb 7, 2015 #3
    i see ! thank you very much
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