Connect an ideal battery across two end of a superconductor?

  • Thread starter anhnha
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  • #1
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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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Answers and Replies

  • #2
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What is an ideal battery? The one whose internal resistance is zero?
 
  • #3
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What is an ideal battery? The one whose internal resistance is zero?
Yes.
 
  • #4
Drakkith
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Mathematically, sure.
Just realize that this is impossible in the real world.
 
  • #5
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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.
 
  • #6
Drakkith
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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.
 
  • #7
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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.
 
  • #8
Drakkith
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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.
 
  • #9
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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.
 
  • #10
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No. There will always be certain effects that make this impossible. An example was given in #5.
 
  • #11
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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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