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electrical engineering materials MCQs

Practise focused electrical engineering materials questions with marked answers for exam preparation and subject revision.

electrical engineering materials Mcqs
1. A highly conductive material must have___________?
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A. easy solderable and drawable quality

B. all of the above

C. highest conductivity

D. good corrosion resistance

E. good mechanical strength

F. lowest temperature co-efficient

2. Which of the following is an advantage of stranded conductor over equivalent single conductor ?
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A. Less liability to break

B. Less liability to kink

C. All of the above

D. Greater flexibility

3. Superconductors are becoming popular for use in________________?
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A. manufacture of bubble memories

B. generating regions free from magnetic field

C. generating electrostatic field

D. generating very strong magnetic field
4. Platinum is used in_____________?
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A. electrical contacts

B. all of the above

C. thermocouple

D. grids of special purpose vacuum tubes

E. heating element in high temperature furnace

5. Due to which of the following factors the brush wear rate is altered ?
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A. All of the above

B. Contact pressure

C. Excessive sparking

D. Speed of the machine

E. Surface conditions of brush and commutator

6. is the property of absorbing moisture from atmosphere_____________?
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A. Viscosity

B. Hygroscopicity

C. Porosity

D. Solubility

7. The conductivity of a metal is determined by____________?
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A. either (A) or (B)

B. the electronic concentration and the mobility of the free electrons

C. none of the above

D. the number of valence electrons per atom

8. In thermocouples which of the following pairs is commonly used ?
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A. Silver-German silver

B. Iron-steel

C. Copper-constantan

D. Aluminium-tin

9. For a hole which of the following statements is incorrect ?
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A. Holes can be considered as a net positive charge

B. Holes may constitute an electric current

C. Holes can exist in certain semiconductors only

D. Holes can exist in any material including conductors
10. At transition temperature the value of critical field is____________?
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A. negative real value

B. zero

C. positive real value

D. complex value

11. is an element used in semiconductors whose atoms have three valence electrons?
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A. Germanium

B. A donor

C. Silicon

D. An acceptor
12. The forbidden gap in an insulator is________________?
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A. small

B. large

C. any of the above

D. nil

13. Due to which of the following reasons aluminium does not corrode in atmosphere ?
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A. Atmospheric oxygen can only diffuse very slowly through the oxide layer which is formed on the surface of aluminium

B. Aluminium is a noble metal

C. No reaction with oxygen occurs ft Any of the above

14. Which of the following materials is used for making coils of standard resistances ?
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A. Platinum

B. Copper

C. Nichrome

D. Manganin
15. __________ is the main constituent of glass?
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A. Fe203

B. Si02

C. AI2O3

D. B2O3

16. The superconductivity is due to____________?
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A. the crystal structure having no atomic vibration at 0K

B. the electrons jump into nucleus at 0K

C. none of the above

D. all electrons interact in the super-conducting state

17. Total number of crystal systems is____________?
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A. 2

B. 12

C. 4

D. 7
18. Addition of 0.3 to 4.5% silicon to iron ________ the electrical resistivity of iron?
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A. increases

B. does not change

C. decreases

19. In graphite, bonding is____________?
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A. Vander Waals

B. metallic

C. Vander Waals and covalent

D. covalent

20. Which of the following materials is preferred for transmitting electrical energy over long distance ?
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A. Aluminium

B. Steel reinforced aluminium

C. Copper

D. Steel reinforced copper

21. High resistivity materials are used in_____________?
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A. all of the above

B. heating elements

C. incandescent lamps

D. precision instruments

E. motor starters

22. Commonly used conducting materials are_____________?
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A. copper

B. aluminium

C. both (A) and (B)

D. copper and silver

E. platinum and gold

23. Spark plug makes use of which of the following materials for insulation ?
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A. Glass

B. Asbestos

C. Porcelain

D. Slate

24. The co-ordination number of a simple cubic structure is______________?
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A. 2

B. 6

C. 4

D. 8

25. Mercury as an electric contact material is_______________?
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A. a liquid

B. a metal

C. a metal liquid

D. a gas

26. Solder is an alloy of______________?
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A. nickel, copper and zinc

B. silver, copper and lead

C. copper and aluminium

D. tin and lead
27. highest conductivity_____________?
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A. all of the above

B. easy solderable and drawable quality

C. lowest temperature co-efficient

D. good corrosion resistance

E. good mechanical strength

28. The conduction of electricity, in semiconductors, takes place due to movement of______________?
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A. negative ions only

B. positive and negative ions

C. electrons and holes

D. positive ions only

29. Selenium is __________ semiconductor?
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A. P-type

B. N-type

C. extrnisic

D. intmisic
30. On which of the following factors does the resistivity of a material depend ?
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A. Length of the conductor

B. Resistance of the conductor

C. All of the above

D. Area of the conductor section

31. Which of the following material is not a semiconductor ?
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A. Gallium-arsenide

B. Selenium

C. Germanium

D. Silica
32. Surface resistance of an insulating material is reduced due to the______________?
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A. smoky and dirty atmosphere

B. humidity in the atmosphere

C. both (A) and (b)

D. neither (A) nor (b)

33. ___________ has the best damping properties?
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A. Diamond

B. High speed steel

C. Mild steel

D. Cast iron
34. Thermocouples are mainly used for the measurement of_____________?
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A. eddy currents

B. resistance

C. coupling co-efficient

D. temperature
35. Steel wire is used as____________?
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A. core wire of ACSR

B. earth wire

C. overhead telephone wire

D. all of the above
36. The minority carrier concentration is largely a function of_____________?
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A. temperature

B. reverse biasing voltage

C. the amount of doping

D. forward biasing voltage

37. Carbon resistors are used extensively because they are____________?
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A. compact

B. inexpensive

C. all of the above reasons

D. easy to make

38. _________ is an example of piezoelectric material?
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A. Glass

B. Quartz

C. Neoprene

D. Corrundum

39. Carbon bearings are used under which of the following conditions ?
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A. Where corrosive chemical action exists

B. All of the above

C. Where high temperature exists

D. Where lubrication is difficult or im-possible

40. __________ is a hard solder?
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A. Copper-zinc

B. Tin-lead

C. None of the above

D. Tin-silver-lead

41. Due to which of the following fact, in India, aluminium is replacing copper ?
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A. Aluminium has lower resistivity than that of copper

B. Aluminium is available in plenty, cheaper and lighter than copper

C. Aluminium has less temperature co-efficient than copper

D. Aluminium is more ductile and malleable than copper

42. Which of the following is a semiconductor material ?
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A. Phosphorous

B. Rubber

C. Aluminium

D. Silicon
43. Which of the following are non-conductors of electricity?
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A. Non-metal solids except carbon

B. Air and most other gases

C. Pure water and liquids in general except mercury

D. All of the above
44. The conductivity of a conductor can be increased by_______________?
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A. increasing its temperature

B. decreasing its temperature

C. increasing its vibration

D. decreasing its vibration

45. A carbon resistor contains_____________?
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A. carbon crystals

B. pulverized coal

C. solid carbon granules

D. finely divided carbon black
46. Copper, even though costly, finds use in the windings of electrical machines because_____________?
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A. copper windings are less bulky and the machines become compact

B. copper points offer low contact resistance

C. all of the above

D. copper can be easily soldered and welded

47. _____________is viscoelastic?
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A. Cast-iron

B. Glass

C. Graphite

D. Rubber
48. The current due to electron flow in conduction band is the hole current in valence band?
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A. less than

B. any of the above

C. greater than

D. equal to

49. The value of critical field below the transition temperature will_______________?
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A. any of the above

B. increase

C. remain unchanged

D. decrease

50. The number of atoms per unit cell in B.C.C. structure is_____________?
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A. 8

B. 2

C. 1

D. 4