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Energy Density of a magnetic field

  1. Jan 24, 2012 #1
    I'm trying to calculate the energy density of a given magnetic field (0.03 T). I'm supposed to use the equation u=B^2/2μ right? Well i'm getting 358.1 A/m (?). Something is wrong here.

    Thanks in advance.
  2. jcsd
  3. Jan 24, 2012 #2


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    Science Advisor

    Magnetic units can be confusing. You might try reading the Wikipedia articles below.

    Or you can take it on faith that if you use SI units throughout, the answer will come out in SI units. In this case, B is in Tesla (which can also be written as Newtons/(Amp-Meter)), and μ0 = 4π*10^-7 Newtons/Amp^2, then the answer U = B^2/(2μ0) will come out in Newtons/m^2, which is the same as Joules/m^3 - i.e an energy density.

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