Magnetics Ques 121
Passage 2
Electrical resistance of certain materials, known as superconductors, changes abruptly from a non-zero value to zero as their temperature is lowered below a critical temperature $T _C(0) . \quad$ An interesting property of superconductors is that their critical temperature becomes smaller than $T _C(0)$ if they are placed in a magnetic field i.e. the critical temperature $T _C(B)$ is a function of the magnetic field strength $B$. The dependence of $T _C(B)$ on $B$ is shown in the figure.
(2010)
- In the graphs below, the resistance $R$ of a superconductor is shown as a function of its temperature $T$ for two different magnetic fields $B _1$ (solid line) and $B _2$ (dashed line). If $B _2$ is larger than $B _1$, which of the following graphs shows the correct variation of $R$ with $T$ in these fields?
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Answer:
Correct Answer: 121.(a)
Solution:
- If $B _2>B _1$, critical temperature, (at which resistance of semiconductors abruptly becomes zero) in case 2 will be less than compared to case 1.
BETA
