Connect an ideal battery across two end of a superconductor?

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Discussion Overview

The discussion centers around the hypothetical scenario of connecting an ideal battery across two ends of a superconductor, exploring the implications for current flow under the assumption of ideal conditions, such as lossless contacts and zero internal resistance in the battery.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants question the definition of an "ideal battery," suggesting it implies zero internal resistance.
  • Others argue that while mathematically one might consider infinite current, this scenario is impossible in the real world due to practical limitations.
  • One participant proposes that the current would increase until the magnetic field generated becomes strong enough to disrupt the superconducting state or cause mechanical failure.
  • Another participant highlights that even a battery with very low resistance would discharge rapidly, potentially leading to an explosion, due to the chemical processes involved in generating electricity.
  • There is a suggestion that an ideal battery could be conceptualized as a special-purpose generator with low internal resistance, although this raises questions about the nature of batteries.
  • Some participants express curiosity about how current is typically generated in superconductors, indicating a potential for further exploration of that topic.
  • One participant asserts that there are always effects that prevent the scenario from yielding infinite current, referencing earlier points made in the discussion.
  • A later reply likens the situation to a paradox, emphasizing that both the concept of an ideal battery and the properties of superconductors impose limits on current flow.

Areas of Agreement / Disagreement

Participants generally agree that the concept of an ideal battery is problematic and that infinite current is not feasible, but multiple competing views remain regarding the implications and definitions involved in the scenario.

Contextual Notes

The discussion highlights limitations in the assumptions made about ideal conditions, the nature of batteries, and the behavior of superconductors under extreme conditions, which remain unresolved.

anhnha
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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?
 
voko said:
What is an ideal battery? The one whose internal resistance is zero?
Yes.
 
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.
 
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.
 
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.
 
  • #10
No. There will always be certain effects that make this impossible. An example was given in #5.
 
  • #11
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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