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Current in superconductors when a voltage is applied.

  1. Feb 26, 2013 #1
    Suppose you a have superconducting loop connected to a 9V battery. What is the current through it? With a resistance of 0Ω, [itex]V = IR[/itex] gives ∞. I don't think that can be right... If it were, [itex]V=\frac{I}{nAe}[/itex] would give an infinite velocity... Does that equation even apply to superconductors?
     
  2. jcsd
  3. Feb 26, 2013 #2

    marcusl

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    Current will be limited by the internal resistance of the battery. This happens for all batteries connected to low impedance loads.
     
  4. Feb 26, 2013 #3
    So if we assume the internal resistance is 1.5Ω how do you calculate the current through the superconductor?
     
  5. Feb 26, 2013 #4

    marcusl

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    I=V/R, just like always. In this case, 9A since a superconductor has 0 resistance.
     
  6. Feb 27, 2013 #5
    Marcus
    There seems to be an arithmetical error here.
     
  7. Feb 27, 2013 #6

    DrDu

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    Superconductors can only carry currents lower than a critical current value. If the current rises above that limit, they become normal conducting.
     
  8. Feb 27, 2013 #7

    marcusl

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    Quite so, I hit the wrong key on my Blackberry. 6A.
     
  9. Feb 27, 2013 #8
    Thank you, very helpful.
     
  10. Feb 27, 2013 #9

    sophiecentaur

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    This is a "irresistible force and immovable object" type of question, if you don't allow something to be non-ideal.
     
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