Creating Magnetic Fields2. Electromagnets

If we have a series of charges moving (which means a current), then we can generate an appreciable magnetic field.

A moving charge (qv) actually can be thought of as a current over a small length:

qv = q(DL/Dt) = I DL

so that we have for each small length:

B = (mo/4p) I DL sin(qIr) / r2

with direction: thumb(field) = hand(current) x fingers(radius).

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