Niobium Metal Becomes a Superconductor (With Electrical Resistance Equal to Zero)

Multiple Choice

Niobium metal becomes a superconductor (with electrical resistance equal to zero) when cooled below 9 K. If superconductivity is destroyed when the surface magnetic field exceeds 0.100 T, determine the maximum current a 2.00-mm diameter niobium wire can carry and remain superconducting. (µ₀ = 4 $\pi$ *10^-7 T.m/A)

A) 2000 A
B) 1000 A
C) 125 A
D) 500 A