If I have a normal copper wire and I run electricity through it a magnetic field is produced around the wire.
2) Is the magnetic field produced in a copper wire proportional to the wire's resistance somehow?
Wrong - at work, we have some electromagnets wound with superconducting wire.
No - only to the current. (Well... the current will be inversely proportional to the circuit resistance, so you could make a case... :-) )
NO
NO
No and no. The magnetic field surrounding a conductor - or even that due to a stream of electrons in free space - is proportional to the current, which simply put is the amount of charge "flowing" past a given point per unit time. In other words, the magnetic field is proportional to the rate at which charge is being transferred along a given path.
A superconducting wire carrying, say, 1A of current would have exactly the same field surrounding it as a conventional conductor carrying the same current. What it would lack, due to the lack of resistance in the conductor, is a *voltage* drop from end to end.
Bob M.
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