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Re: capacitor energy question



If connections are made with ordinary wires in air the
energy is lost in joule heating and sparking when gaps
are being closed. If connections are made with superconductors
in vacuum energy is not lost. But no steady state is reached
immediately. There will be oscillations. Steady state will be
reached after the excess energy has been radiated away.

regards,

sarma.

At 05:03 PM 12/4/98 -0800, you wrote:
Here is a standard problem I'm not convinced I know the answer to:

Charge two different capacitors by connecting in series with an emf.
Disconnect the source and calculate the total energy stored in the
capacitors. Now flip over one of the caps and reconnect it to the
other, and replace the emf with a wire. The charges re arrange
themselves so that the potential is the same across each cap.. Re
calculate the energy. It is lower than the previous value.

Question: where did the energy go? (Standard answer: "re-arranging
the charges"

Harder Question: If a resistor is placed in between the caps before
they are reconnected, the resulting energy is the same as calculated
above. Explain how the final energy can be the same with or without
the obvious Joule-heating that occurs with the resistor?

Ancillary question: Does an isolated oscillating LC tank ciircuit
radiate energy?

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