What happens to current and voltage in a superconductor with zero resistance?

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SUMMARY

The discussion clarifies the behavior of current and voltage in superconductors, emphasizing that while resistance approaches zero, it does not lead to infinite current. The equation V=IR indicates that if resistance (R) is zero, the potential difference (V) must also be zero to avoid a short circuit. Real-world limitations, such as the capacity of voltage sources and internal resistance in generators and batteries, prevent infinite current flow, even in superconductors.

PREREQUISITES
  • Understanding of Ohm's Law (V=IR)
  • Basic knowledge of electrical power equations (P=IV and P=V^2/R)
  • Familiarity with superconductivity and its properties
  • Awareness of limitations in real-world electrical systems
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  • Explore the limitations of voltage sources in electrical circuits
  • Study the effects of internal resistance in batteries and generators
  • Learn about advanced electrical concepts such as power capacity and circuit design
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Electrical engineers, physicists, and students studying superconductivity and electrical systems will benefit from this discussion.

Sagar Singh
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Hi there!
as wee all know V=IR
v= potential difference
I=current
R=resistance
so => I=V/R
and somehow we make Resistance almost equal to 0
then I=V/0
will I become infinity?
or what?

what will happen?
Please clear every situation to me?
 
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Sagar Singh said:
Hi there!
as wee all know V=IR
v= potential difference
I=current
R=resistance
so => I=V/R
and somehow we make Resistance almost equal to 0
then I=V/0
will I become infinity?
or what?

what will happen?
Please clear every situation to me?

You can't do this. If R=0, then you will not have any potential difference, I.e, you have a short! Current doesn't go to "infinity".

Zz.
 
ZapperZ said:
You can't do this. If R=0, then you will not have any potential difference, I.e, you have a short! Current doesn't go to "infinity".

Zz.
Why there will be no potential difference> what is the relation between potential difference and resistance?
 
As resistance gets smaller, current gets larger, yes. But there are limits for real systems.
 
russ_watters said:
As resistance gets smaller, current gets larger, yes. But there are limits for real systems.
LIMITS?? can you please elaborate
 
Sagar Singh said:
LIMITS?? can you please elaborate
Well, let's say you take the output of ALL of the generating stations on Earth. That's going to give you a lot of current capacity. Let's call it 14 zillion amps. OK, now I make R even smaller. Where are you going to get any more current capacity? You can't, so your concept of the equation fails. That's a limit on a real system (and not REALLY a real system, since there are other complications in trying to tie together all the generators on Earth).
 
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Sagar Singh said:
LIMITS?? can you please elaborate
There is also P=IV. Combining that with your expression gives P=V^2/R. So as R goes to 0 so does the power if V is fixed. So the limit is that no real voltage source will actually be able to deliver a constant voltage at arbitrarily low resistance.
 
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DaleSpam said:
There is also P=IV. Combining that with your expression gives P=V^2/R. So as R goes to 0 so does the power if V is fixed. So the limit is that no real voltage source will actually be able to deliver a constant voltage at arbitrarily low resistance.
Power goes toward infiniy, but yes: for real sources, internal limitations get in the way (for batteries: internal resistance, for generators: prime mover power capacity).
 
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We have superconductors thst have zero resistance. We can put a finite current through a superconductor and the voltage difference from one end to the other will be zero. Where is the mystery in that?

We get this question frequently, where people thing that we can set V and I and R to any aribtrary value, and what then? In real life, we can only achieve reasonable value of V and I. R can be measured as the ratio of V to I. No mystery, no infinities.
 
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