JEE Class main Answered

an alloy of niobium and titanium that could easily be made into wire.

Conventional physics does not adequately explain the superconducting state .

Three American researchers - John Bardeen, Leon Cooper and John Schrieffer - established the microscopic theory of superconductivity.  

According to their “BCS” theory, electrons group into pairs through interaction with vibrations of the lattice (so-called “phonons”),

thus forming “Cooper pairs” which move around inside the solid without friction.

The solid can be seen as a lattice of positive ions immersed in a cloud of electrons. As an electron passes through this lattice,

the ions move slightly, attracted by the electron’s negative charge. This movement generates an electrically positive area which,

in turn, attracts another electron thus formin a cooper pair.

In normal conductor , moving electrons are subjected to scattering and collisions , hence we get resistance .

But in super conductor , electrons form ordered pair called cooper pair and moves inside metal without collisions and scattering.

The energy of the electron interaction is quite weak and the pairs can be easily broken up by thermal energy.

This is why superconductivity usually occurs at very low temperature.