electrical engineering MCQs – Page 57

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 Review each marked answer and report any item that may be outdated or unclear.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
1121. Two-value capacitor motor finds increased application as compressor motor in small home air-conditioners because_____________?
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A. it is comparatively cheaper

B. it has almost non-destructible capacitor

C. it has low starting as well as running currents at relatively high power factor

D. it is quiet in operation

1122. In split phase motor main winding is of _____________?
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A. thin wire placed at the top of the slots

B. thick wire placed at the top of the slots

C. thick wire placed at the bottom of the slots

D. thin wire placed at the bottom of the slots

1123. If the capacitor of a single-phase motor is short-circuited_________?
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A. the motor will run

B. the motor will not start

C. the motor will run in reverse direction

D. the motor will run in the same direction at reduced r.p.m

1124. If one-phase of a 3-phase synchronous motor is short-circuited, motor will ______________?
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A. will refuse to start

B. will overheat in spots

C. will fail to pull into step

D. will not come upto speed

1125. The power factor of a synchronous motor is better than that of induction motor because
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A. mechanical load on the motor can be adjusted

B. stator supply is relieved of responsibility of producing magnetic field

C. synchronous motor has large air gap

D. synchronous motor runs at synchronous speed

1126. Which of the following motors is used in tape-recorders ____________?
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A. Capacitor-run motor

B. Reluctance motor

C. Universal motor

D. Hysteresis motor
1127. Centrifugal switch disconnects the auxiliary winding of the motor at about ______ percent of synchronous speed?
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A. 30 to 40

B. 80 to 90

C. 70 to 80

D. 100

1128. The speed control of universal motor used for sewing machines is by____________?
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A. centrifugal mechanism

B. friction

C. tapping the field

D. varying the resistance
1129. For which motor the speed can be controlled from rotor side ?
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A. Squirrel-cage induction motor

B. Slip-ring induction motor

C. Both A. and (b)

D. None of the above

1130. In the circle diagram for induction motor, the diameter of the circle represents____________?
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A. line voltage

B. rotor current

C. slip

D. running torque

1131. Direction of rotation of a split phase motor can be reversed by reversing the connection of__________?
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A. running winding only

B. starting winding only

C. either A. or (b)

D. both A. and (b)

1132. While starting a synchronous motor by induction motor action, field winding is usually_____________?
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A. none of the above

B. connected to D.C. supply

C. short-circuited by low resistance

D. kept open-circuited

1133. The speed characteristics of an induction motor closely resemble the speedload characteristics of which of the following machines?
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A. D.C. shunt motor

B. none of the above

C. D.C. series motor

D. universal motor

1134. Which of the following statements regarding hysteresis motor is in incorrect?
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A. It is extremely sensitive to fluctuations in supply voltage

B. It accelerates from rest to full-speed almost instantaneously

C. It is extremely quiet in operation

D. Its high starting torque is due to its high rotor hysteresis loss

1135. When a 3-phase synchronous generator is supplying a zero power factor lagging load, the armature field affects the main field in the following way
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A. directly opposes it

B. cross-magnetises it

C. augments it directly

D. none of the above

1136. Which of the following methods is easily applicable to control the speed of the squirrel-cage induction motor _____________?
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A. Rotor rheostat control

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

C. By changing the number of stator poles

D. By operating two motors in cascade

1137. The rotor slots, in an induction motor, are usually not quite parallel to the shaft because it_____________?
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A. improves the efficiency

B. improves the power factor

C. helps the rotor teeth to remain under the stator teeth

D. helps in reducing the tendency of the rotor teeth to remain under the stator teeth
1138. The rotor of a hysteresis motor is made of___________?
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A. aluminium

B. chrome steel

C. copper

D. cast iron

1139. Which of the following single-phase motors is suitable for timing and control purposes ?
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A. Reluctance motor

B. Repulsion motor

C. Series motor

D. Universal motor

1140. It is advisable to avoid line-starting of induction motor and use starter because__________?
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A. starting torque is very high

B. it will pick-up very high speed and may go out of step

C. motor takes five to seven times its full load current

D. it will run in reverse direction