# Superconductors MCQ Quiz – Objective Question with Answer for Superconductors

## Objective Question with Answer for Superconductors

1. The magnetization ‘M’ of a superconductor in a filed H is

• (a) extremely small
• (b) -H
• (c) -1
• (d) Zero

Explanation: in superconductors, B=0 or \mu(H+M)=0

\Rightarrow M=-H

2. The maximum power handling capacity of a resistor depends on

• (a) total surface area
• (b) resistance value
• (c) the thermal capacity of the resistor
• (d) the resistivity of the material used in the resistor

Answer: (c) the thermal capacity of the resistor

3. If a small amount of Cu is added to a Ni conductor then the

• (a) the resistivity of Ni will increase at all temperatures because Cu is a better conductor than Ni
• (b) residual resistivity of Ni at low temperatures will increase as Cu atoms act as defect centers
• (c) the resistivity of Ni will increase at all temperatures as Cu destroys the periodicity of Ni and acts as defects
• (d) the resistivity of Ni remains unaltered as Cu atoms give the same number of free electrons as Ni atoms

Answer: (c) the resistivity of Ni will increase at all temperatures as Cu destroys the periodicity of Ni and acts as defects

4. Which one of the following is the best definition of a superconductor?

• (a) it is a material showing perfect conductivity and the Meissner effect below a critical temperature
• (b) It is a conductor having zero resistance
• (c) It is a perfect conductor with the highest diamagnetic susceptibility
• (d) It is a perfect conductor but becomes resistive when the current density through it exceeds a critical value

Answer: (a) it is a material showing perfect conductivity and the Meissner effect below a critical temperature

5. Wire-wound resistances are used when

• (a) precision is essential
• (b) low values are required
• (c) high power rating is necessary
• (d) costly equipment are manufactured

Answer: (c) high power rating is necessary

6. When copper is added to silver in small quantities so as to form an alloy, the resistivity of such an alloy is

• (a) equal to the resistivity of copper
• (b) equal to the resistivity of silver
• (c) greater than the resistivity of copper
• (d) in between the resistivities of silver and copper

Answer: (c) greater than the resistivity of copper

7. The correct sequence of the following materials in the increasing order of magnetic susceptibility is

• (a) Diamagnetic – Ferromagnetic – Paramagnetic – Superconductor
• (b) Ferromagnetic – Paramagnetic – Diamagnetic – Superconductor
• (c) Paramagnetic – Diamagnetic – Superconductor – Ferromagnetic
• (d) Superconductor – Diamagnetic – Paramagnetic – Ferromagnetic

Answer: (d) Superconductor – Diamagnetic – Paramganetic – Ferromagnetic

8. Why does the electric conductivity of a solid solution alloy drop off rapidly with an increased alloy content?

• (a) Because the solid solution has a dielectric nature
• (b) because the solid solution has a less regular structure than that of a pure metal
• (c) Because the solid solution has a higher conductivity than that of the alloying material
• (d) Because the solid solution has a lower molecular weight

Answer: (b) because the solid solution has a less regular structure than that of a pure metal

9. Metal film resistors are made by depositing a very thin layer of metal on a

1. (a) Metal rod
2. (b) Bakelite sheet
3. (c) Ceramic rod
4. (d) Metal sheet

10. What are the correct arrangments of the following alloys in decreasing order of resistivity?

• (a) German silver – constantan – Monel metal
• (b) German silver – Monel metal – constantan
• (c) Constantan – Monel metal – german silver
• (d) Constantan – German silver – Monel metal

Answer: (b) German silver – Monel metal – constantan

11. An intense magnetic field is to be produced by a superconducting coil. Which one of the following is essential?

• (a) The critical temperature Tc must be high so that heating of the coil does not raise the temperature above Tc
• (b) The magnetic field produced by the current should be less than the critical field
• (c) The material should be pure so that its high conductivity allows more current to flow through the coil
• (d) Type-I materials should be used so that superconductivity exists below a sharply defined critical field

Answer: (a) The critical temperature Tc must be high so that heating of the coil does not raise the temperature above Tc

12. The transition temperature of superconducting material is changed by which of the following?

• (a) Electric field
• (b) Magnetic field
• (c) Mechanical stress
• (d) None of these

Answer: (b) Magnetic field,(c) Mechanical stress

13. Which of the folloiwng is not a conducting material?

• (a) Copper
• (b) Tungsten
• (c) Germanium
• (d) Platinum

14. The fuse material used in electrical lines must have which one of the following properties?

• (a) High resistivity
• (b) Low conductivity
• (c) High melting point
• (d) Low melting point

15. Manganin, an alloy of copper and manganese, used in

• (a) Soldering material
• (b) Heating elements
• (c) Ballast resistor
• (d) Standard resistance

16. The materials not having a negative temperature coefficient of resistivity are

• (a) Metals
• (b) Semiconductors
• (c) Insulators
• (d) None of the above

17. In a variable-type carbon resistor the carbon track is formed of a mixture of carbon, resin and

• (a) Clay
• (b) Manganese
• (c) Nickel

18. Intense magnetic field may be produced in a coil b using a

• (a) Normal metal with a large number of turns and sending a large current
• (b) Type-I superconductor with a large number of turns and sending a large current
• (c) Type-II superconductor with a large number of turns and sending a large current
• (d) Type-II superconductor with a large number of turns but limiting the current density below a critical value

Answer: (d) Type-II superconductor with a large number of turns but limiting the current density below a critical value

19. The resistivity of a metal is a function of temperature because

• (a) the electron density varies with the temperature
• (b) the electron gas density varies with the temperature
• (c) the lattice vibration increases with the temperature
• (d) collision of electrons increases as temperature increases

Answer: (d) collision of electrons increases as temperature increases

20. Superconductors are becoming popular of their use in

• (a) generating a very strong magnetic field
• (b) manufacture of bubble memories
• (c) generating electrostatic field
• (d) generating regions free from the magnetic field

Answer: (a) generating a very strong magnetic field

21. Drift velocity in metal is

• (a) inversely proportional to the force on electrons due to the applied electric field
• (b) directly proportional to the mass of an electron
• (c) proportional to the mobility of an electron
• (d) inversely proportional to the strength of the applied electric field

Answer: (c) proportional to the mobility of an electron

22. Which one of the following materials has a temperature coefficient of resistance very close to zero

• (a) Manganin
• (b) Nichrome
• (c) Carbon
• (d) Aluminium

23. The dc resistivity and permeability exhibited by a type-I superconductor are respectively

• (a) Zero and Zero
• (b) Zero and unity
• (c) Unity and Zero
• (d) Unity and Unity

24. In a superconducting magnet, wires of superconducting material are embedded in the thick copper matrix, because while the material is in the superconducting state

• (a) The leakage current passes through the Copper part
• (b) Copper part helps in conducting heat away from the superconductor
• (c) Copper part helps in overcoming the mechanical stress
• (d) Copper acts as an insulating cover for superconductor

Answer: (c) Copper part helps in overcoming the mechanical stress

25. Manganin alloy used for making resistors for laboratory instruments contains

• (a) Copper, Aluminium, and Manganese
• (b) Copper, Nickel, and Manganese
• (c) Aluminium, Nickel, and Manganese
• (d) Chromium, Nickel, and Manganese

Answer: (b) Copper, Nickel, and Manganese

26. The residual resistivity of a metal is

• (A) due to lattice vibrations at high temperature
• (b) due to photon scattering at high temperature
• (c) temperature-dependent
• (d) temperature-independent  Join Our Telegram Group!