Superconductors MCQ Questions|Electrical Engineering Objective Questions

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Superconductors MCQ Questions: Electrical Engineering Objective Questions.

Superconductors MCQ Questions

In superconductivity the conductivity of a material becomes
A.Zero
B.Finite
C.Infinite
D.None of the above
C : Infinite

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In superconductivity, the electrical resistance of material becomes
A.Zero
B.Infinite
C.Finite
D.All of the above
A: Zero


3.Thetemperatureatwhichconductivityofamaterialbecomesinfiniteiscalled
•a.Criticaltemperature
•b.Absolutetemperature
•c.Meantemperature
•d.Crystallizationtemperature
Ans:a.Criticaltemperature
•Criticaltemperatureofasuperconductingmaterialisthetemperatureatwhichthematerialschangesfromnormalconductingstatetosuperconductingstate
•Theconductivityofmaterialbecomesinfiniteatcriticaltemperature

4. In superconductors, the Fermi energy level is
a.Below the ground state
b.Midway between the ground state and first excited state
c.Above first excited state
d.At first excited state
Ans: b -Midway between the ground state and first excited state


5.Thesuperconductingstateisperfectly_____innature.
a.Diamagnetic
b.Paramagnetic
c.Ferromagnetic
d.Ferromagnetic
Ans:a-Diamagnetic
•Superconductorswhencooledbelowacertaintemperatureofferzeroelectricalresistivityandshowperfectdiamagnetism
•Perfectdiamagnetismmeansinducedmagneticfieldcancelsexactlytheappliedmagneticfield


6. Which of the following are the properties of superconductors?
a. They are diamagnetic in nature
b. They have zero resistivity
c.Theyhaveinfiniteconductivity
d. All of the above
Ans–d: All of the above


7. Theminimumamountofcurrentpassedthroughthebodyofsuperconductorinordertodestroythesuperconductivityiscalled
a. Induced current
b.Criticalcurrent
c.Eddycurrent
d.Hallcurrent
Ans: b -Critical current
•When a current is passed through a conductor under a superconducting state,a magnetic field is developed
•Ifthecurrentincreasebeyondcertainvaluethemagneticfieldincreaseuptocriticalvalueatwhichconductorreturnstoitsnormalstate
•Theminimumamountofcurrentpassedthroughthebodyofsuperconductorinordertodestroythesuperconductivity-criticalcurrent


8. The magnetic lines of force cannot penetrate the body of a superconductor,aphe

nomenonisknownas
a.Isotopiceffect
b.BCS theory
c.Meissnereffect
d.London theory
Ans: c -Meissnereffect


9. Thephenomenaofsuperconductorswasfirstdiscoveredby
a)KammerlinghOnnes
b)Neilsbohr
c)RichardSmalley
d)Otto Lehman
Ansa) KammerlinghOnnes
• The phenomena of superconductors were first discovered by Kammerlingh Onnes
• Neils Bohr gave about atomic structure
• Richard Smalley discovered the fullerene by the laser ablation method
•Ottolehmancoinedthenameliquidcrystal.

Superconductors are discovered in the year
a)1900
b)1991
c)1911
d)1905
Ans: 1911
•Superconductorswerediscoveredintheyear1911byKammerlinghOnnes
•HewasaDutchphysicist
•Whenhewasmeasuringtheresistivityofthemercurybelow4.2Khefoundthesuperconductors.
11.Theelectronsheadin___________direction.
a)Same
b)Different
c)Opposite to one another
d)Random
•Theelectronsheadinsamedirectionandcontinuetocarrycurrentendlessly
•Astheyareinsamedirection, they do not collide with each other.
•Ans:a)Samedirection


12. Thenormalmetalpassesintosuperconductingstateat
a) High temperature
b) Low temperature
c) Critical temperature
d) No temperature


•Thenormalmetalpassesintosuperconductingstateatcriticaltemperature
• Most of the metals act as superconductors at low temperatures
Ans: c) Critical temperature


13.Basedonmagneticresponsesuperconductorsareof__________types
a)1
b)2
c)3
d)4
• Based on the magnetic responses, superconductors are of two types
–ideal superconductors or hard superconductors
Ans: b) 2

The ideal superconductors exhibit
a)Meissnereffect
b) Mesmerizing effect
c)Mesomericeffect
d)Monomericeffect
• The ideal superconductors exhibit Meissner effect
•Theexpulsionofmagneticfluxfromtheinteriorofapieceofsuperconductingmaterialasthematerialundergoestransitiontosuperconductingphase
Answer:a

The relation between transition temperature (Tc) and isotopic mass (M) is
(a)Tc∝√M
(b)Tc∝1/√M
(c)Tc∝1/M
(d)Tc∝M
•CriticalortransitiontemperatureTcofasuperconductorvarywithitsisotopicmassM
•Thisvariationiscalledisotopiceffect
Tc∝1/√M
Ans:b)Tc∝1/√M


15. The transition temperature of mercury is
(a)7.5K
(b)12 K
(c)4.8 K
(d)4.2 K
Ans: d) 4.2K


16. Cooper pairs are broken at
(a)0K
(b)Criticaltemperature
(c)Below critical temperature
(d)Above critical temperature
Ans: b) Critical temperature

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