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jsmith613
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Homework Statement
Describe how you would show experimentally that the pd across a capacitor of fixed capacitance is proportional to the charge stored on the plates?
Homework Equations
The Attempt at a Solution
So the most obvious thing would be to place a voltmeter in parallel to the capacitor
To measure the current I could use an ammeter in series with the capacitor.
I know that Q = It but surely the charge stored on a charged capacitor is fixed?
Even If I had a variable resistor in the circuit the current in the circuit would change BUT SO WOULD THE potential difference.
The MS states the following points but it confuses me slightly:
- charge the capacitor through a large resistor at a constant rate
- by using a variable resistor to gradually reduce the resistancd in the circuit
- monitor the current with a micro-ammeter keeping the current constant
- record pd with a voltemter across capacitor
- pd should increase at a constant rate
HOW CAN THE CURRENT STAY CONSTANT - V = IR BUT the power sources does not change so the only thing that changes with R is I :S
please can someone explain to me where I am going wrong