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



Can one insert a PM into a super conducting coil to obtain the energy to
charge the cap.? The plates of the cap. must also be super conducting and
the dielectric should be a vacuum. The sum of the radiative and I^2*R
dissipations is constant?

bc

p.s. I suspect there will be losses associated with inserting the PM. One
one has charged the cap. it discharges through the coil and ejects the PM?

Hugh Haskell wrote:

At 10:28 -0800 2/3/03, David Rutherford wrote:

I don't know much about superconductivity, but shouldn't you be able
charge the capacitor in the absence of resistance (superconducting
circuit). Then, since the energy loss doesn't depend on R, you would
still have to get 1/2 CV^2 for the energy stored on the capacitor. But
where does the other 1/2 CV^2 energy go, in this case? Or maybe the
energy stored on the capacitor in the first place is actually CV^2, not
1/2 CV^2, even in the presence of nonzero R.

Even if you have superconducting wires and no resistor in the
circuit, we still, as far as I know, don't have superconducting
batteries. Every battery has an internal resistance, and in the
absence of resistance anywhere else in the circuit, the (CV^2)/2 that
is lost to the resistor, will be lost to the resistor in the battery.

Sorry, there ain't no free lunch.

Hugh
--

Hugh Haskell
<mailto:haskell@ncssm.edu>
<mailto:hhaskell@mindspring.com>

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