Chronology | Current Month | Current Thread | Current Date |
[Year List] [Month List (current year)] | [Date Index] [Thread Index] | [Thread Prev] [Thread Next] | [Date Prev] [Date Next] |
Two identical parallel plate capacitors are used. One is charged with
charge Q, so the plates have Q and -Q respectively. The other capacitor
is still uncharged. The stored energy of the charged capacitor is CV^2/2,
or Q^2/2C and the stored energy of the other one is zero.
Now perfectly *resistanceless* wires are used to connect the capacitors
as shown, being careful not to add or remove any charge from the system.
The charges redistribute, so that each capacitor has charge Q/2. The
total stored energy (both capacitors) is now
This is half as much stored energy as before. Where did the rest of the
energy go?
The charge redistribution can be accomplished by having the wires in place
and a remote-controlled pair of switches complete the connection. No
mechanical work need be done by the agent performing this operation.