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Re: There's work, and then there's work



David Rutherford wrote:

Where does the L come from in a superconducting DC circuit that only has
a battery and a capacitor?

It comes from the circuit itself. Current flowing in the circuit
will produce magnetic flux linking the circuit.

For more information, please consult an introductory physics textbook.

The L and C components of the impedance create an LC circuit which
oscillates and radiates the 'missing' 1/2 CV^2.

Has this 1/2 CV^2 radiated energy been measured in the case of a
charging capacitor in a superconducting circuit?

I'd be very surprised if it had. On the other hand, the experimental
record is clear that oscillating currents radiate electromagnetic
energy and that they do so in a way that is in exceptionally precise
quantitative agreement with the predictions of standard
electromagnetic theory.

If the missing energy is not radiated away, then there are two
remaining explanations:

1) Some of the energy "goes" into some other form.

2) The law of conservation of energy is wrong.

Lacking *any* reason whatsoever to think otherwise, I'm going to
place my money on the "radiated away" option, but you are certainly
free to try to do the experiment and see for yourself. In contrast,
however, to the previously suggested calorimetry experiment (which
you showed little interest in doing) *this* would be a difficult
experiment to perform.

In any event, you shouldn't expect anyone to show the least interest
in a theory that predicts something VERY different unless you come
armed with some convincing and reproducible experimental evidence and
can show how your theory squares with the current well-verified
predictions in most every other situation.

--
A. John Mallinckrodt http://www.csupomona.edu/~ajm
Professor of Physics mailto:ajm@csupomona.edu
Physics Department voice:909-869-4054
Cal Poly Pomona fax:909-869-5090
Pomona, CA 91768-4031 office:Building 8, Room 223