# Tagged Questions

A measure of the rate at which electric charge is transported (especially through a circuit), it has units of charge/time.

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### Current due to External Electric Field

Assume a conductor in a rectangle shape for simplicity. Now, if I only choose one side of this rectangle having length L, and apply external electrical field ∑ only to it(along with the wire), what ...
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### Damping of motion of a conductor [closed]

The motion of a conductor is damped when allowed to oscillate between magnetic pole pieces. Two questions:- How is the damping force produced by eddy current? Why eddy current is undesirable in ...
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### Why is Ampere not a derived SI unit? [duplicate]

From my understanding, Ampere is amount of elementary charge per time. So, you should be able to derive it from mol, which is amount, and seconds, which is time. My question: Why is Ampere a base ...
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### Gravitomagnetic railgun

Would a gravitomagnetic analogue of a railgun work as expected, in theory? Consider replacing the electric currents on each rail with mass currents. Then place a mass between the rails, moving with ...
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### Current on both sides of a capacitor

When a capacitor is connected to a DC circuit, what ensures that the current on both sides of the capacitor is the same? When charges arrive at one end of the capacitor they stop moving; presumably ...
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### Why is $\nabla \cdot \vec{J} = 0$ where $J$ is the current density?

This is quoted from Purcell's Electricity & Magnetism: ...if charge forever pours out of, or into, a fixed volume, the charge density inside must grow infinite, unless some compensating charge ...
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### Why is resistance across a load the V per I rather than the V per Q?

There is a load that resists the flow of electrons. This causes a voltage drop, meaning it creates a potential difference between the 2 sides of itself. This property, a load creating a voltage drop, ...