Q: The temperature bellow which a material becomes a superconductor is called

\$\textbf{Critical temperature}\$ is the temperature below which metals when taken exhibit zero resistivity and turns into a superconductor. The critical temperature varies with the individual material. Because these materials have no electrical resistance, meaning electrons can travel freely through them, they can carry large amounts of electrical current for long periods of time without losing energy as heat. The transition is so sudden and complete that it appears to be a transition to a different phase of matter; known as the superconducting phase.

Q: The dependence of the critical temperature for superconductivity upon

\$\alpha =\cfrac { M }{ \Delta M } \times \cfrac { \Delta { T }_{ c } }{ { T }_{ c } } \\ \$Where \$\alpha = \$ isotopic co-efficient \$\Delta M=M-{ M }^{ * } \$ difference between isotopic mass \${ T }_{ c }=\$ critical temperature of superconductor \$\Delta { T }_{ c }=\$ change in critical temperature Clearly critical temperature dependent on the isotopic mass.

Q: Which of the following is true regarding superconductivity?

\$1.\$ This critical magnetic field is strongly correlated with the critical temperature for the superconductor which in turn correlated with the bandgap.\$2.\$ As it is the nature of superconductor to exclude magnetic fields so long as the applied field does not exceed their critical magnetic field.\$3.\$ This critical magnetic field is tabulated for \$0K\$ and decrease from the magnitude with increasing temperature, reaches zero at the critical temperature for superconductivity.\$4.\$ The critical magnetic field at any temperature below the critical temperature is given by the relationship,\$Bc\approx Bc\left( 0 \right) \left[ 1-\left( \cfrac { T }{ Tc } \right) ^{ 2 } \right] \$where,\$Bc \rightarrow\$ Critical Magnetic Field\$T \rightarrow\$ Temperature\$Tc \rightarrow\$ Critical TemperatureSo, the superconductivity state cannot exist in the presence of a magnetic field greater than a critical value, even at absolute zero.

Question 1

The temperature bellow which a material becomes a superconductor is called

Accepted Answer

$\textbf{Critical temperature}$ is the temperature below which metals when taken exhibit zero resistivity and turns into a superconductor.  The critical temperature varies with the individual material. Because these materials have no electrical resistance, meaning electrons can travel freely through them, they can carry large amounts of electrical current for long periods of time without losing energy as heat. The transition is so sudden and complete that it appears to be a transition to a different phase of matter; known as the superconducting phase.

Question 2

When a superconductor is placed in a weak external magnetic field H, and cooled below its transition temperature,

Accepted Answer

When a superconductor is placed in a weak external magnetic field $H$, and cooled below its transition temperature, the magnetic field is ejected from it and this phenomenon is called effect Meissner effect. The ability of this expulsion effect of the magnetic field is determined by the nature of equilibrium formed by the neutralization within the unit cell of a superconductor.

Question 3

A conductor behave as a super conductor

Accepted Answer

Superconductors are conductors with exactly zero resistance. Conductors put under temperature above critical temperature behave as a super conductor.

Question 4

Critical temperature can be defined as the

Accepted Answer

Critical temperature is that temperature at or below which a gas can be liquefied by pressure alone and above which a gas cannot be liquefied by pressure alone.

Question 5

The cause of dimegnetism is :

Accepted Answer

Due to orbital motion of electrons.

Question 6

The value of resistivity of super conductor is

Accepted Answer

In superconductors, the resistance drops abruptly to zero when the material is cooled below its critical temperature. Thus resistivity of superconductors is zero below its critical temperature.

Question 7

The dependence of the critical temperature for superconductivity upon

Accepted Answer

$\alpha =\cfrac { M }{ \Delta M } \times \cfrac { \Delta { T }_{ c } }{ { T }_{ c } } \ $Where $\alpha = $ isotopic co-efficient             $\Delta M=M-{ M }^{ * } $ difference between isotopic mass              ${ T }_{ c }=$ critical temperature of superconductor              $\Delta { T }_{ c }=$ change in critical temperature Clearly critical temperature dependent on the isotopic mass.

Question 8

Define transition temperature.

Accepted Answer

The temperature at which electrical resistivity of the material suddenly drops of zero and the material changes from normal conductor to a super conductor is called the Transition temperature or critical temperature ${ T }_{ C }$.

Question 9

Which of the following is true regarding superconductivity?

Accepted Answer

$1.$ This critical magnetic field is strongly correlated with the critical temperature for the superconductor which in turn correlated with the bandgap.$2.$ As it is the nature of superconductor to exclude magnetic fields so long as the applied field does not exceed their critical magnetic field.$3.$ This critical magnetic field is tabulated for $0K$ and decrease from the magnitude with increasing temperature, reaches zero at the critical temperature for superconductivity.$4.$ The critical magnetic field at any temperature below the critical temperature is given by the relationship,$Bc\approx Bc\left( 0 \right) \left[ 1-\left( \cfrac { T }{ Tc }  \right) ^{ 2 } \right] $where,$Bc \rightarrow$ Critical Magnetic Field$T \rightarrow$ Temperature$Tc \rightarrow$ Critical TemperatureSo, the superconductivity state cannot exist in the presence of a magnetic field greater than a critical value, even at absolute zero.

Question 10

Which of the following is the use of superconductor?

Accepted Answer

The uses of superconductors are as follows:Superconductors are used to make extremely powerful electromagnets to accelerate charged particles very fast.Used in Maglev (magnetic levitation) trains. These work because a superconductor repels a magnetic field so a magnet will float above a superconductor &#8211; this virtually eliminates the friction between the train and the trackThe development of superconductors has improved the field of MRI as the superconducting magnet can be smaller and more efficient than an equivalent conventional magnet.They are also used in microwaves.

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