What is the deal with superconductors?

Question

If you have a superconducting circuit , so R = 0 , this means V= 0, right? because V=IR. But if there is no voltage...what is causing the electrons to keep going round? or do they just keep on going like they were?

Answer 1

It's not that R IS EQUAL TO 0, it's that R IS CLOSE TO 0.  

So yes, there IS some resistance, but it is very very small. Thus it take a very very small voltage to move an electron ther same distance that it used to, needing a bigger resistance and bigger voltage

Therofore, superconductor circuitry is much more efficient, requiring less power to do the same amount of work, or doing more work with the same amount of power.

Answer 2

The reason why superconductivity occurs is still not completely understood, although a great deal of work has been done on the subject. The resistance is exactly zero. However, the formula V = IR is a classical result, whereas superconductivity is a quantum-mechanical phenomenon. As a result, V = IR cannot be a perfect description of a superconductor - in fact in this case it doesn't even come close if you write it as I = V/R (since R is zero). True enough, it doesn't take any voltage at all for electrons to travel through a superconducting wire. Voltage refers only to a potential difference as in classical physics. However, in quantum mechanics, the energy of an electron is lowered if it has more room to occupy (consider for example the particle-in-a-box model), so electrons will continue circulating around a superconducting wire with no application of voltage.