electrical engineering MCQs – Page 229

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 Review each marked answer and report any item that may be outdated or unclear.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
4561. The ratio of active power to apparent power is known as factor__________?
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A. demand

B. power

C. load

D. form

4562. The apparent power drawn by an A.C. circuit is 10 kVA and active power is 8 kW. The reactive power in the circuit is_________?
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A. 8 kVAR

B. 6 kVAR

C. 4 kVAR

D. 16 kVAR

4563. The power factor of a D.C. circuit is always__________?
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A. less than unity

B. zero

C. greater than unity

D. unity
4564. The r.m.s. value of pure cosine function is_________?
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A. 0.707 of peak value

B. zero

C. same as peak value

D. 0.5 of peak value

4565. At very low frequencies a series R-C circuit behaves as almost purely___________?
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A. capacitive

B. inductive

C. resistive

D. none of the above

4566. The series and parallel resonance on L-C circuit differs in that_________?
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A. series resonance needs a high-resistance source for sharp increase in current

B. parallel resonance needs a low-resistance source for a sharp increase in impedance

C. parallel resonance needs a low-resistance source for a sharp rise in line current

D. series resistance needs a low-resistance source for sharp rise in current
4567. In a sine wave the slope is constant_______?
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A. between 180 and 270

B. between 90 and 180

C. between 0 and 90

D. no where
4568. The purpose of a parallel circuit resonance is to magnify________?
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A. frequency

B. power

C. voltage

D. current

4569. The safest value of current the human body can carry for more than 3 second is_________?
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A. 9 mA

B. 15 mA

C. 4 mA

D. 25 mA

4570. In any A.C. circuit always__________?
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A. actual power is more than reactive power

B. reactive power is more than actual power

C. reactive power is more than apparent power

D. apparent power is more than actual power
4571. What will be the phase angle between two alternating waves of equal frequency, when one wave attains maximum value the other is at zero value________ ?
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A. 45

B. 90

C. 0

D. 180

4572. The frequency of domestic power supply in Pakistan is_________?
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A. 200 Hz

B. 50 Hz

C. 60 Hz

D. 100 Hz

4573. If resistance is 20 Q. and inductance is 27 in a R-L series circuit, then time constant of this circuit will be________?
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A. 10 s

B. 100 s

C. 0.001 s

D. 0.1 s
4574. A small coil lies inside a large coil. The two coils are horizontal concentric and carry currents in opposite directions. The large coil will experience______________?
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A. No resultant force

B. A torque about horizontal axis

C. An upward force along the axis

D. A torque about vertical axis

4575. Non inductive resistances are used in decreasing______________?
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A. Self inductance

B. Mutual inductance

C. Magnetic fields

D. Heating effect

4576. An aeroplane of wingspan 10m flies from the equator towards the North Pole. The wings are perpendicular to the vertical component of the earths magnetic field (B = 410-5T). At maximum speed an emf of 96mV is induced across the wing tips. The maximum speed of the aeroplane is____________?
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A. 38.4msec-1

B. 200msec-1

C. 384msec-1

D. 150msec-1

4577. The only difference between construction of D.C generator and A.C generator is that of_______________?
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A. commutator

B. coil

C. carbon brushes

D. magnetic field

4578. A.C and D.C have the same______________?
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A. heating effect through a resistance

B. effect while passing through an inductance

C. effect in charging a capacitor

D. effect in charging a battery

4579. A coil with negligible resistance has 50V across it with 10 mA. The inductive reactance is_____________?
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A. 500 ohms

B. 50 ohms

C. 5000 ohms

D. 1000 ohms

4580. If current in a conductor increases then according to Lenzs law self-induced voltage will____________?
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A. tend to decrease the amount of cur-rent

B. aid the applied voltage

C. produce current opposite to the in-creasing current

D. aid the increasing current