# connect an ideal battery across two end of a superconductor?

by anhnha
Tags: battery, connect, ideal, superconductor
 P: 138 Hi, What will happen if I connect an ideal battery across two ends of a superconductor? Assume all contacts are ideal, lossless. Is the current infinitive?
 PF Patron Thanks P: 4,490 What is an ideal battery? The one whose internal resistance is zero?
P: 138
 Quote by voko What is an ideal battery? The one whose internal resistance is zero?
Yes.

PF Patron
P: 10,403

## connect an ideal battery across two end of a superconductor?

Mathematically, sure.
Just realize that this is impossible in the real world.
 PF Patron Thanks P: 4,490 Then the current will grow till the magnetic field becomes so strong that the superconductor will stop being a superconductor, or is torn apart by mechanical stress from the growing magnetic field, whichever happens first.
 PF Patron P: 10,403 There's also the fact that it isn't possible to have a battery with 0 resistance. Even with a resistance close to zero, the battery would discharge so fast it would explode. It is using a chemical reaction to generate electricity, after all.
 PF Patron Thanks P: 4,490 An ideal battery cannot be chemical almost by definition. There are in fact special-purpose generators with very low internal resistance that can generate huge currents, albeit for very brief periods of time. I guess we could imagine this "ideal battery" is such a generator.
 PF Patron P: 10,403 Well, then it wouldn't be a battery at all, would it? I'm curious as to how they even generate current in a superconductor normally. Is it induced somehow? But perhaps that is a question for another thread.
 P: 138 Hi, For example, assuming that we have the battery ideal with no internal resistance and all contacts, wires are ideal (no resistance). Then, theoretically, the voltage/current across/through two ends of the wire is indeterminate, right? And this configuration even impossible in theory.
 PF Patron Thanks P: 4,490 No. There will always be certain effects that make this impossible. An example was given in #5.
 Mentor P: 15,589 This is merely a modern version of the "unstoppable force against an immovable object" paradox. There is no such thing as an ideal battery. There are superconductors, but even those can only support a finite current density before they cease being superconducting. Both of those realities will prevent infinite current.

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