23. At low temperature, Lead behaves as a : A.Semi conductor B.Superconductor C.Insulator D.Conductor
Option B Solution: Lead exhibit superconducting phase transitions at low temperatures of 7.2 Kelvin. This discovery was made in 1913. At this temperature (known as critical temperature), the electrical resistivity of lead drops to zero. The transition is so sudden and complete that it appears to be a transition to a different phase of matter; this superconducting phase is described by the BCS theory.
