# How to measure the charges stored in a capacitor when the plate space changes?

1. Aug 9, 2009

### leo_ng

1. Basically this was a question directed by my subject lecturer. He needs me to describe a method on how to measure the amount of charges stored versus the spacing between the plates of a capacitor.

2. There are many types of ways and equations to measure the amount of charges stored but I'am not sure how to do the same when dealing with different spacings between the plates of a capacitor.

3. Unfortunately, due to lack of research on this particular issue and lack of further knowledge, I haven't a clue on how to tackle the problem.

2. Aug 9, 2009

### fleem

If you know the charge in a plate, and you move that plate away or toward the other plate, the charge does not change. This is because charge is conserved, because charge is a measure of the number of charged particles that are present in the object.

EDIT: If you don't know the charge to begin with but you are suppose to figure it out from other given things, then there are some simple equations you can use. start here:

$$C= Q/V$$

$$E = \frac{1}{2} * C * V^2$$

Last edited: Aug 9, 2009
3. Aug 10, 2009

### leo_ng

Oh now I see it, all this while after some reading I was kinda wondering why wasn't the charge affected when voltage is supplied to the circuit. Thanks for the answer.