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

[Ludwik Kowalski <kowalskil@MAIL.MONTCLAIR.EDU>]

On Saturday, Jan 25, 2003, David Rutherford asked:

> Could someone please refer me to experimental evidence that
>  the total energy stored by a capacitor is 1/2 CV^2. Thanks.

The experiment to perform can be done in this way:

1) Find a capacitor of known C (as large as possible).
2) Charge it to a known V (close to Vmax for your C).
3) Discharge it through R inside a common water calorimeter.
4) Repeat 2 and 3 as many times a necessary till the water
    temperature changes, by dT that you can measure.
5) Use that dT, and the known parameters of your calorimeter,
    to calculate the amount of thermal energy. Is very close to
    CV^2 or is it very close to 0.5*C*V^2

A styrofoam cup with ~50 cc of water, plus any kind of
thermometer, will be sufficient. Working at the level of
+/- 10% accuracy would be OK for your purpose.
Please share the result of your measurement with us.
Ludwik Kowalski