What does potential difference in a capacitor really mean? Is it the work done in bringing Q charge from infinity?
What does potential difference in a capacitor really mean? Is it the work done in bringing Q charge from infinity?
Potential energy of charge q at a point (in the presence of field due to any charge configuration)is the work done Potential refers to a particular point - or set of points which are "equipotential". So you can talk about the potential of one of the capacitor plates (because each is an equipotential surface) but not the potential of the capacitor (because when charged the 2 plates are at different potentials).
When talking about a capacitor, potential usually means POTENTIAL DIFFERENCE V between the 2 plates. This measures the total amount of work W required to charge them to +Q and −Q. Charging could be done by bringing charges from infinity in turn onto the plates, or by transferring the charge by some means from one plate to the other across the gap, or by applying a battery which transfers charge from one plate to the other through wire connections. In all three cases, the work done is the same, and the potential difference which is created between the plates is V=W/Q.
The charged capacitor has the "potential" to do work. If a small charge +dq is released from the +ve plate, work Vdq can be extracted by transferring it to the −ve plate. For example, the work can be dissipated in a resistor connected between the plates.
by the external force (equal and opposite to the electric force)in bringing the charge q from infinity to that point.
Potential refers to a particular point - or set of points which are "equipotential". So you can talk about the potential of one of the capacitor plates (because each is an equipotential surface) but not the potential of the capacitor (because when charged the 2 plates are at different potentials).
When talking about a capacitor, potential usually means POTENTIAL DIFFERENCE V between the 2 plates. This measures the total amount of work W required to charge them to +Q and −Q. Charging could be done by bringing charges from infinity in turn onto the plates, or by transferring the charge by some means from one plate to the other across the gap, or by applying a battery which transfers charge from one plate to the other through wire connections. In all three cases, the work done is the same, and the potential difference which is created between the plates is V=W/Q.
The charged capacitor has the "potential" to do work. If a small charge +dq is released from the +ve plate, work Vdq can be extracted by transferring it to the −ve plate. For example, the work can be dissipated in a resistor connected between the plates.
by the external force (equal and opposite to the electric force)in bringing the charge q from infinity to that point.
