electrical engineering MCQs – Page 231

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 Review each marked answer and report any item that may be outdated or unclear.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
4601. A dynamo converts______________?
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A. magnetic energy into mechanical energy

B. electrical energy into mechanical energy

C. magnetic energy into electrical energy

D. mechanical energy into electrical energy
4602. Which of the following circuit element stores energy in the electromagnetic field ?
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A. Variable resistor

B. Inductance

C. Resistance

D. Condenser

4603. The self-inductance of the coil may be defined as equal to the e.m.f. induced in volts when the current in the circuit changes at the rate of unit Weber turns
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A. Yes

B. No
4604. A laminated iron core has reduced eddy-current losses because____________?
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A. the laminations are stacked vertfcally

B. the magnetic flux is concentrated in the air gap of the core

C. the laminations are insulated from each other

D. more wire can be used with less D.C. resistance in coil

4605. The direction of induced e.m.f. can be found by_____________?
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A. Flemings right hand rule

B. Laplaces law

C. Kirchhoff s voltage law

D. Lenzs law
4606. Which of the following is not a unit of inductance ?
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A. Henry

B. Volt second per ampere

C. All of the above

D. Coulomb/volt ampere
4607. Both the number of turns and the core length of an inductive coil are doubled. Its self-inductance will be_____________?
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A. unaffected

B. quadrupled

C. halved

D. doubled
4608. The self inductances of two coils are 8 mH and 18 mH. If the co-efficients of coupling is 0.5, the mutual inductance of the coils is______________?
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A. 6 mH

B. 4 mH

C. 5 mH

D. 12 mH

4609. The practical illustration of the phenomenon of mutual induction is____________?
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A. D.C dynamo

B. A.C generator

C. transformer

D. induction coil

4610. An alternating current or voltage________________?
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A. varies in magnitude alone

B. changes its magnitude continuously and reverses its direction of flow after regularly recurring intervals.

C. fluctuates off and on

D. changes its direction again and again

4611. The emf induced in a conductor of unit length moving with unit velocity at right angles to a magnetic field is equal to_____________?
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A. Motional emf

B. Magnetic flux density

C. Mutual induction

D. Torque

4612. Power loss in actual transformer is due to_________________?
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A. Back emf

B. Eddy currents and magnetic hysterias

C. Small output

D. Soft iron core

4613. Air-core coils are practically free from______________?
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A. hysteresis losses

B. eddy current losses

C. both (A) and (B)

D. none of the above

4614. An open coil has_____________?
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A. zero resistance and high inductance

B. infinite resistance and zero inductance

C. infinite resistance and normal inductance

D. zero resistance and inductance

4615. An e.m.f. of 16 volts is induced in a coil of inductance 4H. The rate of change of current must be______________?
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A. 32 A/s

B. 16 A/s

C. 64 A/s

D. 4 A/s
4616. In case all the flux from the current in coil 1 links with coil 2, the co-efficient of coupling will be____________?
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A. zero

B. 1.0

C. 2

D. 0.5

4617. The law that the induced e.m.f. and current always oppose the cause producing them is due to____________?
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A. Coulomb

B. Lenz

C. Newton

D. Faraday

4618. emf induced in a circuit according to Faradays law depends on the_____________?
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A. maximum magnetic flux

B. initial magnetic flux

C. rate of change of magnetic flux

D. change in magnetic flux

4619. Energy stored in a magnetic field is given by______________?
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A. LI2/2

B. LI2

C. IL2

D. L2I/2

4620. A 200 turn coil has an inductance of 12 mH. If the number of turns is increased to 400 turns, all other quantities (area, length etc.) remaining the same, the inductance will be___________?
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A. 6 mH

B. 24 mH

C. 48 mH

D. 14 mH