electrical engineering MCQs – Page 3

Practise multiple-choice questions from electrical engineering for competitive examinations and subject revision. Review each marked answer and report any item that may be outdated or unclear.

electrical engineering Mcqs
1. economics of power generation2. analog electronics3. solid state switching circuits4. parallel circuits5. switchgear and protection6. op amp circuits7. transistor audio power amplifiers8. electrostatics9. heating and welding10. multi stage transistor amplifiers11. passive filters12. network theorems13. regulated d c power supply14. a c fundamentals circuits and circuit theory15. electromagnetic induction16. power electronics17. magnetism and electromagnetism18. transformers19. modulation and demodulation20. d c generators21. semiconductor theory22. single phase induction motors23. semiconductor diode24. hybrid parameters25. digital electronics26. oscillators27. earthing or grounding28. single stage transistor amplifiers29. d c motors30. transistor biasing31. amplifiers with negative feedback32. basic electrical33. electronic instruments34. synchronous motors35. field effect transistors fet36. magnetic circuit37. control systems38. industrial drives39. power generation40. series parallel circuits41. transistor tuned amplifiers42. electrical engineering materials43. rectifiers and converters44. integrated circuits45. scr silicon controlled rectifiers46. cables47. polyphase induction motors48. measurement and instrumentation49. transistors50. electrical machine design51. electrolysis and storage of batteries52. electric traction53. transmission and distribution
41. Double fourier series analysis of PWM is_____________?
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A. Two dimensional functions

B. All of these

C. Three dimensional functions

D. One dimensional functions

42. The maximum firing angle in the half wave controlled regulator is_____________?
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A. 210 degree

B. 180 degree

C. 200 degree

D. 190 degree

43. A single phase full bridge inverter can operated in load commutation mode in case load consist of______?
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A. RLC overdamped.

B. RLC critically damped

C. RL.

D. RLC underdamped.
44. A string of n parallel SCRs is operated at 72 KA, the rating of each SCR is 1 KA. If derating factor of the string is 0.1. value of n will be___________?
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A. 70

B. 60

C. 90

D. 80
45. The typical value of SCR for modern alternator is____________?
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A. 0.5.

B. 1.2.

C. 1.0.

D. 1.5.

46. If 1 A current flows in a circuit, the number of electrons flowing through this circuit is
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A. 0.625 1019

B. 0.625 10-<sup>19</sup>

C. 1.6 10<sup>19</sup>

D. 1.6 10-<sup>19</sup>

47. If the gate voltage of an SCR is removed, then the_______________?
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A. anode current increases

B. anode current does not decrease at all

C. cathode current increases

D. anode current decreases

48. A PNPN device having two gates is ___________?
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A. Triac

B. Diac

C. BCS

D. SUS

49. Maximum power loss occurs during_________________?
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A. rise time

B. spread time

C. all

D. delay time

50. A single phase ac dc converter is also known as____________?
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A. inverter

B. rectifier

C. regulator

D. chopper

51. If a shunt motor is started with its field winding open then?
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A. It will rotate at less speed as that with its field winding closed

B. It will rotate at dangerously high speed

C. It will rotate at the same speed as that with its field winding closed

D. None of these

52. The resistance of a conductor of diameter d and length l is R ?. If the diameter of the conductor is halved and its length is doubled, the resistance will be
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A. 2R ?

B. 8R ?

C. 4R ?

D. R ?

53. The turn-on time of an SCR with inductive load is 20 s. The puls train frequency is 2.5 KHz with a mark/space ratio of 1/10, then SCR will___________?
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A. Turn on

B. Turn on if pulse frequency us increased to two times

C. Not turn on

D. Turn on if inductance is removed

54. A Triac is a ______________?
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A. 3 terminal bilateral switch

B. 2 terminal bilateral switch

C. 3 terminal bidirectional switch

D. 2 terminal switch

55. In reverse blocking mode of a thyristor______?
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A. junction J1 and J2 is in forward bias and J3 is in reverse bias.

B. junction J3 is in forward bias and J1, J2 in reverse bias.

C. junction J2 is in reverse bias and J1, J3 is in forward bias.

D. junction J1, J3 is in reverse bias and J2 is in forward bias.
56. A step up chopper has input voltage 110 V and output voltage 150 V. The value of duty cycle is_____?
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A. 0.27

B. 0.32

C. 0.67

D. 0.45

57. Capacitor does not allow the sudden change of ?
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A. current

B. power

C. voltage

D. None of the above

58. In single phase VSI, the harmonic which is not present is____________?
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A. 7th

B. 3rd

C. 2nd

D. 5th

59. Very large values of modulation index (greater than 3.24) lead to___________?
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A. Trapezoidal AC output voltage

B. Sine AC output voltage

C. Square AC output voltage

D. Triangular AC output voltage

60. The latching current of GTO should be of order
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A. 2:00 AM

B. 500 mA

C. 1:00 AM

D. 100 mA