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facenian
facenian is offline
#1
Feb6-13, 06:53 AM
P: 205
Hello, I have this problem. I calculated the dipole energy of a dipole moment in an external field using the equation [itex]U_m=\frac{1}{2}\int\vec{A}\vec{J}dr^3=\frac{1}{2} \vec{\mu}.\vec{B}[/itex] however when the force on a dipole is calculated using [itex]\int\vec{J}\times\vec{B}dr^3[/itex] the formula obteined for the energy is [itex]-\vec{\mu}.\vec{B}[/itex]
I don't understand the difference, are they supposed to be defferent?
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