Where is it gone ?

[Andre Kesteloot]

Assume you have two identical, loss-free 1uF capacitors, one charged 
to 10V, the other is discharged.

You then connect the two in parallel so the total C is now 2uF - 
charge will flow from the charged capacitor into the discharged
capacitor.

Assuming charge Q is conserved, and that Q=CV, the voltage must now be
5V.

But the stored energy in a capacitor =1/2CV^2, so with the single
charged capacitor, the stored energy is 1/2 x 1uF x 100 = 50uJ, while 
with both capacitors in parallel it is only 1/2 x 2uF x 25 = 25uJ. 
So where has the other 25uJ gone? 

André
(from the RSGB LF Reflector)