Q5Electrical Materials
Question
Q.5. Explain superconductivity.
Answer
Superconductivity is the complete disappearance of electrical resistance in certain materials below a critical temperature Tc, accompanied by expulsion of magnetic flux (Meissner effect).
Superconductivity is the phenomenon exhibited by certain materials (e.g., mercury below 4.2 K, niobium alloys, YBCO ceramics) in which the electrical resistance drops abruptly to exactly zero when the material is cooled below its characteristic critical temperature (Tc). In the superconducting state, current can persist indefinitely without any driving voltage, and the material also expels magnetic flux from its interior (the Meissner effect), behaving as a perfect diamagnet. The superconducting state is destroyed if temperature, magnetic field, or current density exceed their critical values (Tc, Hc, Jc).