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## Homework Statement

A parallel-plate capacitor C , with plate separation d , is given an initial

charge ±Q[itex]_{0}[/itex]. It is then connected to a resistor R, and discharges, Q(t)=Q[itex]_{0}[/itex] e[itex]^{-t/RC}[/itex]

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(a) What fraction of its energy Q[itex]_{0}[/itex][itex]^{2}[/itex]/2C does it radiate away?

## Homework Equations

The equations for an electric dipole, involving the retarded time.

## The Attempt at a Solution

I have been at this for hours and don't know what to do. I think I should treat the capacitor as a dipole at a very great distance away and integrate over a massive sphere as one does for an oscillating dipole. However this was taking me an age, and you get to the point where coshx is the only real solution so rather than being able to time average cos^2(x) as usual, you just can't do that.

There must be something I'm missing. I know the energy loss from the capacitor Q[itex]_{0}[/itex][itex]^{2}[/itex]/2C , and I know the energy stored in the capacitor, but they appear to be the same amount, when logically they should be different, witht the difference in energy equalling the anergy radiated away. Any help would be great.