Answer to Question #168437 in Electricity and Magnetism for beth

Question

16.) The superconducting solenoid in an MRI scanner has inductance 342 mH and normally carries 1.85 kA. Copper conductors with resistance 21.6 mΩ are embedded in the superconducting coils. If superconductivity is suddenly lost and copper takes over the conduction, how long will it take for the current to drop below 250 A?

Answer 1

Answer

Time taken by it can be obtain as

$t=-\frac{L}{R}ln(\frac{i(t) }{i_0})$

$t=-\frac{342}{21.6}ln(\frac{250 }{1.85\times10^3}) =31.7s$