Oh dear... Gene Mosca's remarks force me to further revise my position
with respect to emf. I confess that I'd rather sit on an anthill then try
to explain the action of a chemical cell; I'm generally happy simply to
consider it magic. (I think, however, that I recall hearing Gene do so at
an AAPT meeting once upon a time.) On the other hand, I believe we can at
least partially dispose of "motional emf" by noting that we are trying to
do the standard path integral of E in a frame in which the path itself is
moving. If we do that integral in the proper frame we will find a
background electric field (v x B) which precisely accounts for the
observed emf.
John
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A. John Mallinckrodt http://www.intranet.csupomona.edu/~ajm
Professor of Physics mailto:ajmallinckro@csupomona.edu
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