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

4621. Mutually inductance between two magnetically-coupled coils depends on____________?
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A. cross-sectional area of their common core

B. permeability of the core

C. the number of their turns

D. all of the above
4622. Which one of the following functions like a motor ?
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A. galvanometer

B. all of above

C. ammeter

D. voltmeter

4623. Two coils have self-inductances of 10 H and 2 H, the mutual inductance being zero. If the two coils are connected in series, the total inductance will be_____________?
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A. 8 H

B. 6 H

C. 12 H

D. 24 H

4624. An average voltage of 10 V is induced in a 250 turns solenoid as a result of a change in flux which occurs in 0.5 second. The total flux change is____________?
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A. 2 Wb

B. 0.2 Wb

C. 20 Wb

D. 0.02 Wb
4625. Which of the following works on torque on the current carrying conductor placed in magnetic field ?
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A. ammeter

B. galvanometer

C. voltmeter

D. all of the above
4626. Reversing the field or the current will reverse the force on the conductor
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A. Yes

B. No

4627. The polarity of the induced voltage can be determined by using the left-hand generator rule
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A. Yes

B. No

4628. For long distance transmission the transformer used is_____________?
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A. Input voltage and output voltage remain same

B. Step down

C. Step up

D. Amplifier is used

4629. As per Faradays laws of electromagnetic induction, an e.m.f. is induced in a conductor whenever it_______________?
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A. lies in a magnetic field

B. lies perpendicular to the magnetic flux

C. cuts magnetic flux

D. moves parallel to the direction of the magnetic field

4630. A.C can not be used for_______________?
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A. producing light

B. Producing magnetic field

C. Magnetizing iron

D. producing heat

4631. A conductor 2 meters long moves at right angles to a magnetic field of flux density 1 tesla with a velocity of 12.5 m/s. The induced e.m.f. in the conductor will be____________?
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A. 25V

B. 15 V

C. 50V

D. 10 V

4632. Which of the following uses electric energy and does not convert it into any other form ?
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A. motor

B. transformer

C. D.C generator

D. A.C generator

4633. Two coils have inductances of 8 mH and 18 mH and a co-efficient of coupling of 0.5. If the two coils are connected in series aiding, the total inductance will be______________?
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A. 38 mH

B. 40 mH

C. 48 mH

D. 32 mH

4634. Weber is the unit of_____________?
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A. magnetic flux

B. Magnetic field intensity

C. self-inductance

D. magnetic induction

4635. A 500 turns solenoid develops an average induced voltage of 60 V. Over what time interval must a flux change of 0.06 Wb occur to produce such a voltage ?
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A. 5 s

B. 0.1 s

C. 0.5 s

D. 0.01 s

4636. Which of the following circuit elements will oppose the change in circuit current ?
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A. Inductance

B. All of the above

C. Capacitance

D. Resistance

4637. A conductor carries 125 amperes of current under 60 to a magnetic field of 1.1 tesla. The force on the conductor will be nearly______________?
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A. 50 N

B. 120 N

C. 480 N

D. 240 N

4638. The emf induced in a coil by a changing magnetic flux may have unit as______________?
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A. ms-1A

B. kgm2s-1A-1

C. kgms2A-1

D. ms-2A-1

4639. An electric current induced within the body of a conductor when that conductor either moves through a non uniform magnetic field or in a region where there is a change in magnetic flux is called_____________?
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A. None of the above

B. Back emf

C. Induced current

D. Eddy current
4640. For electroplating we use_________________?
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A. any source

B. A D.C source

C. an A.C source

D. all of the above

4641. Higher the self-inductance of a coil_____________?
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A. lower the e.m.f. induced

B. lesser its weber-turns

C. greater the flux produced by it

D. longer the delay in establishing steady current through it
4642. The alternating current has frequency of 106 Hz in such a way that time period for completion of cycle is_______________?
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A. 1.5Hzs

B. 1Hzs

C. 106sec

D. 1sec

4643. In an iron cored coil the iron core is removed so that the coil becomes an air cored coil. The inductance of the coil will_____________?
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A. initially increase and then decrease

B. remain the same

C. increase

D. decrease
4644. Self-inductance of a long solenoid is______________?
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A. ?oN2

B. BA

C. ?oN2A

D. ?oN2/A

4645. Current changing from 8 A to 12 A in one second induced 20 volts in a coil. The value of inductance is___________?
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A. 10 mH

B. 5 mH

C. 5 H

D. 10 H

4646. Self inductance of a coil depends upon________________?
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A. current flowing

B. voltage produce

C. all

D. number of turns per unit length

4647. Lagging of changes in the magnetization of a substance behind changes in the magnetic field as the magnetic field is varied is known as magnetic_____________?
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A. Hysteresis

B. Flux

C. Permeability

D. Retaintivity

4648. A.C cannot be used for_______________?
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A. magnetizing and electroplating

B. all the above

C. producing light

D. producing heat

4649. If the coil is wound on an iron core the flux through it will_______________?
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A. remain the same

B. become zero

C. decrease

D. increase
4650. A coil induces 350 mV when the current changes at the rate of 1 A/s. The value of inductance is___________?
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A. 250 mH

B. 150 mH

C. 3500 mH

D. 350 mH