|Nov6-08, 02:26 AM||#1|
Potential energy for magnetic fields
1. The problem statement, all variables and given/known data
A circular 10 turn coil that has a radius of 0.05 m and current of 5A lies in the xy plane with a uniform magnetic field B = 0.05 T i + 0.12 T k (i and k are the unit vectors). What's the potential energy for the system???
2. Relevant equations
U = -m*B where m is the dipole moment = I*A
3. The attempt at a solution
B = sqrt((0.05 T)^2 + (0.12 T)^2) = 0.13 T
So for this I would get U = -0.00511 J, but the answer key says -0.000472 J... where's the mistake???
|Nov6-08, 03:03 AM||#2|
I'm assuming from the answer that the magnetic moment must not be aligned with the field, but how do you know this given the problem? And how do you calculate this?
|Oct5-10, 02:48 PM||#3|
Well, we have to keep in mind that -m*B is actually a "dot product". ;)
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