Question

Which of the following behaves as a superconductor at temperature $ < 10K $ .
(A) Copper
(B) Iron
(C) Lead
(D) Steel

Answer 1

Hint: The term "superconductor" refers to a substance that conducts electricity without resistance. Unlike more common conductors like copper or steel, a superconductor can sustain a current indefinitely without losing any energy. Aluminium, niobium, magnesium diboride, cuprates such as yttrium barium copper oxide, and iron pnictides are all instances of superconductors.

Complete Step By Step Answer:
The ability of certain materials to conduct electric current with virtually no resistance is known as superconductivity. Low temperatures are required for a material to behave as a superconductor. H. K. Onnes, a Dutch physicist, discovered superconductivity in 1911. With a critical temperature of $ {\text{7}}{\text{.2K}} $ , lead is a Type I superconductor. Despite the fact that these superconductors may conduct currents with zero resistance, their utility is restricted due to low critical magnetic fields. Because of the zero resistivity, if a current is generated in a superconducting lead ring, it will remain.
Since, the critical temperature of lead is $ {\text{7}}{\text{.2K}} $ therefore the temperature is less than 10 kelvin.
So, the correct option in this question is ‘C’ i.e. the Lead.

Note:
Superconductors, on the other hand, are materials that are normally poor conductors at room temperature but become zero resistance when the temperature is reduced to extremely low levels. This is why good conductors cannot become superconductors. The major distinction between a conductor and a superconductor is that a superconductor has no electrical resistance while conductors have some.