Question

Niobium metal becomes a superconductor (with zero electrical resistance) when cooled below 5.1 K. The permeabilty of free space is 1.25664 × 10−6 N/A 2 . If superconductivity is destroyed when the surface magnetic field exceeds 0.11 T, determine the maximum current a 2.5 mm diameter niobium wire can carry and remain superconducting.

Answer 1

687.5 A

Step-by-step explanation:

We are given that

`\mu_0=1.25664* 10^(-6)N/A^2`

Magnetic field,B=0.11 T

Diameter,d=2.5mm

Radius,r=
`(d)/(2)=(2.5)/(2)mm=1.25* 10^(-3) m`

`1mm=10^(-3) m`

We know that current in coil

`I=(2\pi rB)/(\mu_0)`

Substitute the values

`I=(2\pi* 1.25* 10^(-3)* 0.11)/(1.25664* 10^(-6))`

`I=687.5 A`