Find the minimum possible diameter for the wire of pureniobium so that the T=0 critical field would not be exceeded if thewire carried a current of 4.5 amps. Recall that the magnetic field at the surface of a uniformcylindrical wire of radius R carrying a current I is asfollows: B=oI / 2R Find the minimum possible diameter for the wire of pureniobium so that the T=0 critical field would not be exceeded if thewire carried a current of 4.5 amps. Recall that the magnetic field at the surface of a uniformcylindrical wire of radius R carrying a current I is asfollows: B=oI / 2R
Explanation / Answer
the magnetic field at the surface of the uniform cylindricalwire is B = (oI/2R) or R = (oI/2B) o= 4 * 10^-7 N/A^2 I = 4.5 A B is the critical magnetic field = 2060*10-4tesla at T = 0 the minimum possible diameter is for the wire is D = 2 * R plug values and do caliculations