electrical engineering MCQs – Page 341

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 Review each marked answer and report any item that may be outdated or unclear.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 generation 2. analog electronics 3. solid state switching circuits 4. parallel circuits 5. switchgear and protection 6. op amp circuits 7. transistor audio power amplifiers 8. electrostatics 9. heating and welding 10. multi stage transistor amplifiers 11. passive filters 12. network theorems 13. regulated d c power supply 14. a c fundamentals circuits and circuit theory 15. electromagnetic induction 16. power electronics 17. magnetism and electromagnetism 18. transformers 19. modulation and demodulation 20. d c generators 21. semiconductor theory 22. single phase induction motors 23. semiconductor diode 24. hybrid parameters 25. digital electronics 26. oscillators 27. earthing or grounding 28. single stage transistor amplifiers 29. d c motors 30. transistor biasing 31. amplifiers with negative feedback 32. basic electrical 33. electronic instruments 34. synchronous motors 35. field effect transistors fet 36. magnetic circuit 37. control systems 38. industrial drives 39. power generation 40. series parallel circuits 41. transistor tuned amplifiers 42. electrical engineering materials 43. rectifiers and converters 44. integrated circuits 45. scr silicon controlled rectifiers 46. cables 47. polyphase induction motors 48. measurement and instrumentation 49. transistors 50. electrical machine design 51. electrolysis and storage of batteries 52. electric traction 53. transmission and distribution

6801. Which of the following methods is easily applicable to control the speed of the squirrel-cage induction motor _____________?
0

A. By injecting e.m.f. in the rotor circuit

B. Rotor rheostat control

C. By changing the number of stator poles

D. By operating two motors in cascade

6802. The good power factor of an induction motor can be achieved if the average flux density in the air gap is___________?
0

A. absent

B. large

C. small

D. infinity

6803. The shape of the torque/slip curve of induction motor is__________?
0

A. rectangular parabola

B. straigth line

C. parabola

D. hyperbola

6804. The starting torque of a 3-phase squirrel cage induction motor is____________?
0

A. twice the full load torque

B. 1.5 times the full load torque

C. equal to full load torque

6805. The starting torque of a three phase induction motor can be increased by__________?
0

A. increasing slip

B. increasing current

C. both A. and (b)

D. none of the above

6806. Size of a high speed motor as compared to low speed motor for the same H.P. will be__________?
0

A. any of the above

B. smaller

C. bigger

D. same

6807. A 3-phase slip ring motor has____________?
0

A. double cage rotor

B. wound rotor

C. any of the above

D. short-circuited rotor

6808. Short-circuit test on an induction motor cannot be used to determine___________?
0

A. copper losses

B. transformation ratio

C. windage losses

D. power scale of circle diagram

6809. In a squirrel cage motor the induced e.m.f. is___________?
0

A. dependent on the shaft loading

B. dependent on the number of slots

C. slip times the stand still e.m.f. induced in the rotor

D. none of the above

6810. Which motor is preferred for use in mines where explosive gases exist ?
0

A. Induction motor

B. Air motor

C. Synchronous motor

D. D.C. shunt motor

6811. The speed of a squirrel-cage induction motor can be controlled by all of the following except_____________?
0

A. changing winding resistance

B. changing number of poles

C. reducing supply voltage

D. changing supply frequency

6812. Which is of the following data is required to draw the circle diagram for an induction motor ?
0

A. Block rotor test, no-load test and stator resistance test

B. Block rotor test and no-load test

C. Block rotor test only

D. No load test only

6813. The circle diagram for an induction motor cannot be used to determine____________?
0

A. efficiency

B. power factor

C. output

D. frequency

6814. For which motor the speed can be controlled from rotor side ?
0

A. Squirrel-cage induction motor

B. Slip-ring induction motor

C. Both A. and (b)

D. None of the above

6815. The efficiency of an induction motor can be expected to be nearly____________?
0

A. 80 to 90%

B. 60 to 90%

C. 99%

D. 95 to 98%

6816. Insertion of reactance in the rotor circuit_______?
0

A. increases starting torque but maxi-mum torque decreases

B. increases starting torque as well as maximum torque

C. reduces starting torque as well as maximum torque

D. increases starting torque but maxi-mum torque remains unchanged

6817. The torque of an induction motor is___________?
0

A. proportional to the square of the slip

B. directly proportional to slip

C. inversely proportional to slip

D. none of the above

6818. The frame of an induction motor is usually made of____________?
0

A. cast iron

B. aluminium

C. silicon steel

D. bronze

6819. The cogging of an induction motor can be avoided by____________?
0

A. auto-transformer starter

B. having number of rotor slots more or less than the number of stator slots (not equal)

C. using DOL starter

D. proper ventilation

6820. The torque developed by a 3-phase induction motor least depends on__________?
0

A. shaft diameter

B. rotor power factor

C. rotor current

D. rotor e.m.f.

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