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

## Main Question or Discussion Point

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?

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What is an ideal battery? The one whose internal resistance is zero?

What is an ideal battery? The one whose internal resistance is zero?
Yes.

Drakkith
Staff Emeritus
Mathematically, sure.
Just realize that this is impossible in the real world.

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.

Drakkith
Staff Emeritus
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.

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.

Drakkith
Staff Emeritus
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.

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.

No. There will always be certain effects that make this impossible. An example was given in #5.

Dale
Mentor
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.