Some Pysics Insights
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On this page, I've collected together a few items having to do with magnetism.

The original reason for working these things out was to provide some "backing" for an essay on the impossibility of building an "over-unity" magnetic motor.  I've since collected them together here because they are more closely related to each other than they are to anything else on the site.

A derivation of the formulas for the torque and force on a magnetic dipole in a magnetic field, along with a brief proof that the force on a permanent dipole due to a nonuniform magnetic field is conservative.Force on a Dipole
A magnetic dipole is normally modeled as a current loop.  However, it's sometimes simpler to work with a dipole modeled as two monopoles.  On this page I show that the fields from the two models are the same; hence, one can use them interchangeably in certain situations, even though the "two-charge" model is unrealistic, as there are no magnetic monopoles.Two-Charge
Derivation of the field of a dipole, in rectangular and polar coordinates.Dipole Field
Electric and magnetic fields of a uniformly moving charge, and a (somewhat imperfect) derivation of the Biot-Savart law of magnetostatics.Uniformly
Moving Charge

Page created on 1/7/07.  Last updated on 1/17/2007.