Current in superconductors when a voltage is applied.

In summary, the conversation discusses the current through a superconducting loop connected to a 9V battery, with a resistance of 0Ω. It is mentioned that the current will be limited by the internal resistance of the battery and that the equation V=\frac{I}{nAe} may not apply to superconductors. The conversation also mentions that superconductors can only carry currents lower than a critical value and that there was an arithmetic error in the previous calculation of 9A, with the correct value being 6A. The conversation ends with the question of whether an "irresistible force and immovable object" scenario applies to this situation.
  • #1
JackA7X
6
0
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?
 
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  • #2
Current will be limited by the internal resistance of the battery. This happens for all batteries connected to low impedance loads.
 
  • #3
So if we assume the internal resistance is 1.5Ω how do you calculate the current through the superconductor?
 
  • #4
I=V/R, just like always. In this case, 9A since a superconductor has 0 resistance.
 
  • #5
Marcus
There seems to be an arithmetical error here.
 
  • #6
Superconductors can only carry currents lower than a critical current value. If the current rises above that limit, they become normal conducting.
 
  • #7
syhprum said:
Marcus
There seems to be an arithmetical error here.
Quite so, I hit the wrong key on my Blackberry. 6A.
 
  • #8
Thank you, very helpful.
 
  • #9
This is a "irresistible force and immovable object" type of question, if you don't allow something to be non-ideal.
 

What is a superconductor?

A superconductor is a material that is able to conduct electricity with zero resistance when it is cooled below a certain critical temperature. This allows for current to flow through the material without any loss of energy.

Why is current important in superconductors?

Current is important in superconductors because it is the flow of electricity that allows for the zero resistance effect to occur. When a voltage is applied, a current is induced in the material that allows for the continuous flow of electricity without any loss of energy.

How does current behave in a superconductor when a voltage is applied?

In a superconductor, when a voltage is applied, the current initially increases rapidly until it reaches its maximum value. After this point, the current levels off and remains constant, even as the voltage is increased. This behavior is known as the critical current.

What factors affect the current in superconductors when a voltage is applied?

The current in superconductors when a voltage is applied is affected by several factors, including the material's critical temperature, the strength of the applied magnetic field, and the geometry of the superconductor. In addition, impurities or defects in the material can also affect the current-carrying capacity.

What are the practical applications of current in superconductors?

The zero resistance property of superconductors makes them extremely useful in a variety of applications, including magnetic levitation trains, MRI machines, and particle accelerators. They are also used in power transmission and storage, as they can carry large currents without any energy loss.

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