Current in superconductors when a voltage is applied.

[JackA7X]

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

 

[marcusl]

Current will be limited by the internal resistance of the battery. This happens for all batteries connected to low impedance loads.

 

[JackA7X]

So if we assume the internal resistance is 1.5Ω how do you calculate the current through the superconductor?

 

[marcusl]

I=V/R, just like always. In this case, 9A since a superconductor has 0 resistance.

 

[syhprum]

Marcus
There seems to be an arithmetical error here.

 

[DrDu]

Superconductors can only carry currents lower than a critical current value. If the current rises above that limit, they become normal conducting.

 

[marcusl]

Marcus
There seems to be an arithmetical error here.

Quite so, I hit the wrong key on my Blackberry. 6A.

 

[JackA7X]

Thank you, very helpful.

 

[sophiecentaur]

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