In the graphs below, the resistance R of a superconductor is shown as a function of its temperature T for two different magnetic fields B1 (solid line) and B2 (dashed line). If B2 is larger than B1, which of the following graphs shows the correct variation of R and T in these fields?
A
B
C
D
Hard
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Updated on : 2022-09-05
Solution
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Correct option is A)
Resistance usually varies directly with temperature.
But when considering superconductors, the least temperature is Tc(0).
In presence of B, Tc decreases. But that doesn't say anything about general R and T relation.
Only info we have is Tc(B2) < Tc(B1) if B2>B1. (from observing the graph)