# How would you find the time taken for a steady current for a superconductor? For part (c) I need to find the time taken for the solenoid to gain maximum magnetic field strength. However, since it uses superconducting wires, the total resistance is zero, so how would I be able to calculate the duration before the current is steady using $$I(t) = I_0(1-e^{-t/\tau})$$ for $$\tau = L/R$$? Since the limit as $$R$$ goes to zero implies the limit of $$I(t)$$ as $$R$$ goes to zero is $$I_0$$, should we conclude that and initial $$I_0 = 0$$ implies that you can never add current since the inductance will be infinite or something? I know this is not the case but what is the alternative? Should I try to leave a small $$\delta$$ of resistance?

• While your question is interesting, I think you're misinterpreting what the exercise is asking. It's not asking about the behavior of the superconducting material, but just a $P = E/t$ question based on the power of the supply. – BowlOfRed Oct 1 at 20:39