Why do superconductors have zero resistance?

Answer 1

There are many different superconductor theories which have been suggested for different superconductors. One, called the BCS theory (named after its creators: Bardeen, Cooper and Schrieffer) suggests that electrons in a superconductor are grouped in pairs called Cooper pairs. The motions of all the pairs within a superconductor produces a system that functions as a single entity. Therefore, a voltage applied to the superconductor would cause all Cooper pairs to move, forming an electric current. When the voltage is removed, the current continues to flow because the pairs encounter no opposition.

Answer 2

Yes, zero means zero. Here's a wiki clip about an exception (sort of): In a class of superconductors known as Type II superconductors, including all known high-temperature superconductors, an extremely small amount of resistivity appears at temperatures not too far below the nominal superconducting transition when an electrical current is applied in conjunction with a strong magnetic field, which may be caused by the electrical current. This is due to the motion of vortices in the electronic superfluid, which dissipates some of the energy carried by the current. If the current is sufficiently small, the vortices are stationary, and the resistivity vanishes. The resistance due to this effect is tiny compared with that of non-superconducting materials, but must be taken into account in sensitive experiments. However, as the temperature decreases far enough below the nominal superconducting transition, these vortices can become frozen into a disordered but stationary phase known as a "vortex glass". Below this vortex glass transition temperature, the resistance of the material becomes truly zero.

Answer 3

Zero Electrical Resistance

Answer 4

superconductors would have the least resistance because the electrons are able to move from one attraction to the next in the pathway without having a momentum break when passing from one stable ring to the next.

Answer 5

Because at a certain very cold temperature temperature ,about 4.8 kelvin I believe, certain materials will become superconductive
meaning their electrical resistance goes to 0, if the Resistance is zero there is no losses. This phenomenon is used in most MRI scanners. The magnet which is basically a electric magnet is made from coils of copper and niobium wire. The vessel which holds these coils of wire is filled with liquid helium. The current is then fed into the wire coils and using special switches the current is caught in a endless loop and since there is basically no losses the current is trapped there for as long as the vessel is at liquid helium temperature. A typical super conducting magnet has over 400 amps trapped inside. The only area that has Resistance is where the wires are joined together.

Answer 6

The simplest method to measure the electrical resistance of a sample of some material is to place it in an electrical circuit in series with a current source I and measure the resulting voltage U across the sample. The resistance of the sample is given by Ohm's law as . If the voltage is zero, this means that the resistance is zero and that the sample is in the superconducting state.

Superconductors are also able to maintain a current with no applied voltage whatsoever, a property exploited in superconducting electromagnets such as those found in MRI machines. Experiments have demonstrated that currents in superconducting coils can persist for years without any measurable degradation. Experimental evidence points to a current lifetime of at least 100,000 years, and theoretical estimates for the lifetime of persistent current exceed the lifetime of the universe.

Answer 7

Because if they didn't have zero resistance.... they would not be superconductors.

Answer 8

zero resistance = zero impedance = zero friction = greater speeds, hence super conductors !

Answer 9

Nothing really has zero resistance.