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Re: magnetic fields



Michael Crofton wrote:
.. . .

So the dipole moments of the atoms point in the same direction as the
applied B field. But, the magnetic fields created by the atomic dipoles
point in the opposite direction as their dipole moment: the dipole
moment is from S to N; the field they create is directed from N to S.
Since the magnetic fields created by the atomic dipoles point in the
opposite (antiparallel) direction as their dipole moment, they also
point in the opposite direction as the external field of the horseshoe
magnet. I would reason, therefore, that the field created by the
dipoles in the paramagnetic material COUNTERACTS the field of the
horseshoe magnet.
.. . .

Michael,
There is a crucial difference between the fields of an Electric
dipole and a Magnetic dipole (We speak here of two separated +/- charges
vs. separated N/P magnetic poles, apropos of your model). The "interior"
field of the electric dipole is antiparallel to the dipole moment vector;
the "interior" field of the magnetic dipole is paralell to the dipole
moment vector. (Cuz electric lines start on + and stop on - charges, while
magnetic lines are continuous, with no beginning or end - a distinction
lost in the "bar magnet" model of the magnetic dipole.)

Bob Sciamanda sciamanda@edinboro.edu
Dept of Physics
Edinboro Univ of PA http://www.edinboro.edu/~sciamanda/home.html