Maximum current a superconductor can carry

[Parad0x88]

Homework Statement

Niobium metal becomes a superconductor when cooled below 9 K. Its superconductivity is destroyed when the magnetic field inside the superconductor exceeds 0.100 T. Determine the maximum current a 3.00-mm-diameter niobium wire can carry and remain fully superconducting, in the absence of any external magnetic field.

Homework Equations

So we know if B > 0.1 T, the superconductor is destroyed, thus we have to find an I that will not make it exceed such figure. The formula I was thinking of using is:

B = (μ₀I)/(2∏r)

r = 1.5 mm, or 0.00015m
B = 0.100 T
Solve for I

The Attempt at a Solution

Solving for I: (B2∏r)/(μ₀) = I



Does that make sense? I can't find much info in my book about superconductors to guide me

 

[Parad0x88]

Anyone? I'm trying to do as good as possible in these assignments, but this one has got me stumped :/

 

[aralbrec]

That's the way I would do it. You'll have to assume a DC current is flowing so that the current is spread evenly across the wire cross section. Keep in mind you will be calculating B inside the wire.. how much of the current is enclosed when applying Ampere's Law?