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
751. The speed of a D.C. shunt motor can be increased by_______________?
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A. reducing the resistance in the armature circuit

B. reducing the resistance in the field circuit

C. increasing the resistance in armature circuit

D. increasing the resistance in field circuit
752. Which of the following test can be performed on DC series motor?
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A. Brake test

B. Swinburne test

C. Field test

D. Hopkinson test

753. Flywheel is used with D.C. compound motor to reduce the peak demand by the motor, compound motor will have to be_____________?
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A. under compounded

B. level compounded

C. cumulatively compounded

D. differentially compounded

754. The ratio of starting torque to full-load torque is least in case of____________?
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A. compound motors

B. none of the above

C. shunt motors

D. series motors

755. Which D.C. motor will be preferred for machine tools ?
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A. Differential compound motor

B. Cumulative compound motor

C. Series motor

D. Shunt motor
756. When two D.C. series generators are running in parallel, an equilizer bar is used________________?
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A. to increase the speed and hence generated e.m.f.

B. to increase the series flux

C. so that two similar machines will pass approximately equal currents to the load

D. to reduce the combined effect of ar-mature reaction of both machines

757. During rheostat braking of D.C. series motors_____________?
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A. motor is run as a generator

B. motor is run at reduced speed

C. motor is reversed in direction

758. The voltage drop for which of the following types of brush can be expected to be least ?
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A. None of the above

B. Metal graphite brushes

C. Graphite brushes

D. Carbon brushes

759. For the same H.P. rating and full load speed, following motor has poor starting torque_____________?
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A. shunt

B. cumulativelycompounded

C. series

D. differentially compounded
760. In a D.C. generator the critical resistance refers to the resistance of_____________?
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A. field

B. brushes

C. load

D. armature

761. Which of the following generating machine will offer constant voltage on all loads?
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A. Self-excited generator

B. Separately excited generator

C. Level compounded generator

D. All of the above

762. For a D.C. shunt motor if the excitation is changed_______________?
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A. torque will remain constant

B. torque will change but power will remain constant

C. torque and power both will change

D. torque, power and speed, all will change

763. The speed of a motor falls from 1100 r.p.m. at no-load to 1050 r.p.m. at rated load. The speed regulation of the motor is______________?
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A. 2.36%

B. 6.77%

C. 8.84%

D. 4.76%
764. D.C. generator generally preferred for charging automobile batteries is______________?
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A. shunt generator

B. any ofthe above

C. long shunt compound generator

D. series generator

765. According to Flemings left-hand rule, when the forefinger points in the direction of the field or flux, the middle finger will point in the direction of_________________?
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A. current in the conductor aovtaat of conductor

B. none of the above

C. resultant force on conductor

766. Which of the following tests will be suitable for testing two similar D.C. series motors of large capacity ?
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A. Hopkinsons test

B. Swinburnes test

C. Field test

D. Brake test

767. The losses occurring in a D.C. generator are given below. Which loss is likely to have highest proportion at rated load of the generator ?
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A. field copper loss

B. armature copper loss

C. hysteresis loss

D. eddy current loss

768. The series field of a short-shunt D.C. generator is excited by_______________?
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A. armature current

B. shunt current

C. external current

D. load current
769. Wave winding is composed of_______________?
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A. any odd number of conductors

B. any even number of conductors

C. that even number which is exact multiple of poles + 2

D. that even number which is exact multiple of poles

770. If a D.C. motor is connected across the A.C. supply it will_______________?
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A. run at lower speed

B. burn due to heat produced in the field winding by .eddy currents

C. run at normal speed

D. not run

771. Armature reaction of an unsaturated D.C. machine is_____________?
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A. crossmagnetising

B. none of above

C. demagnetising

D. magnetising

772. The essential condition for parallel operation of two D.C. generators is that they have ________________?
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A. the same operation r.p.m.

B. the same drooping voltage characteristics

C. same percentage regulation

D. same kW rating

773. For both lap and wave windings, there are as many commutator bars as the number of_____________?
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A. armature conductors

B. poles

C. winding elements

D. slots

774. Flashing the field of D.C. generator means:______________?
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A. making the magnetic losses of forces parallel

B. increasing flux density by adding extra turns of windings on poles

C. creating residual magnetism by a D.C. source

D. neutralising residual magnetism

775. Differentially compound D.C. motors can find applications requiring___________?
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A. low starting torque

B. frequent on-off cycles

C. variable speed

D. high starting torque

776. Sparking, is discouraged in a D.C. motor because_____________?
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A. it increases the input power con-sumption

B. commutator gets damaged

C. both A. and B.

D. none of the above

777. Which D.C. motor is preferred for elevators ?
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A. Differential compound motor

B. Shunt motor

C. Cumulative compound motor

D. Series motor

778. D.C. series motors are used______________?
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A. where load changes frequently

B. in none of the above situations

C. where constant operating speed is needed

D. where load is constant

779. In a separately excited generator supplying rated load the armature reaction.
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A. is always present

B. is always absent

C. none of the above

D. may be sometimes present

780. In a D.C. generator, the iron losses mainly take place in___________/
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A. yoke

B. commutator

C. armature rotor

D. armature conductors

781. The field coils of D.C. generator are usually made of_____________?
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A. carbon

B. cast iron

C. mica

D. copper
782. The armature core of a D.C. generator is usually made of__________________?
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A. non-ferrous material

B. copper

C. cast-iron

D. silicon steel
783. The armature torque of the D.C. shunt motor is proportional to____________?
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A. field flux only

B. armature current only

C. both A. and B.

D. none of the above

784. Buses, trains, trolleys, hoists, cranes require high starting torque and therefore make use of_____________?
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A. all of above motors

B. D.C. shunt motor

C. D.C. series motor

D. induction motor

785. In the case of lap winding resultant pitch is____________?
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A. division of front pitch by back pitch

B. difference of front and back pitches

C. multiplication of front and back pitches

D. sum of front and back pitches

786. Which of the following law/rule can he used to determine the direction of rotation of D.C. motor ?
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A. Coloumbs law

B. Lenzs law

C. Faradays law

D. Flemings left-hand rule
787. The type of D.C. motor used for shears and punches is_____________?
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A. series motor

B. shunt motor

C. differential compoutid D.C. motor

D. cumulative compound D.C. motor
788. In a D.C. shunt motor, speed is______________?
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A. proportional to the square of the current

B. independent of armature current

C. inversely proportional to the armature current

D. directly proportional to the armature current

789. Which D.C. motor has got maximum self relieving property ?
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A. Differentially compounded motor

B. Series motor

C. Shunt motor

D. Cumulatively compounded motor

790. If B is the flux density, I the length of conductor and v the velocity of conductor, then induced e.m.f. is given by______________?
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A. Bl2v2

B. Blv

C. Bl2v

D. Blv2

791. Laminations of core are generally made of________________?
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A. case iron

B. stainless steel

C. carbon

D. silicon steel
792. Which generator would you prefer for feeding long D.C. transmission lines ?
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A. Flat compound generator

B. Shunt generator

C. Series generator

D. Over compound generator
793. In a D.C. generator the magnetic neutral axis coincides with the geometrical neutral axis, when_______________?
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A. the generator runs on overload

B. the generator runs on full load

C. there is no load on|he generator

D. the generator runs on designed speed

794. To get the speed of D.C, motor below the normal without wastage of electrical energy is used?
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A. Ward Leonard control

B. any of the above method

C. none of the above method

D. rheostatic control

795. Which motor has the poorest speed control?
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A. Differentially compounded motor

B. Series motor

C. Cumulatively compounded motor

D. Shunt motor

796. The main factor which leads to unstable parallel operation of flat and over compounded generators is_____________?
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A. their rising voltage characteristics

B. unequal speed regulation of their primemovers

C. unequal series field resistances

D. unequal number of turns in their series field windings

797. If a D.C. shunt motor is working at full load and if shunt field circuit suddenly opens____________?
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A. this will result in excessive speed, possibly destroying armature due to excessive centrifugal stresses

B. this will make armature to take heavy current, possibly burning it

C. nothing will happen to motor

D. motor will come to stop

798. If a D.C. motor is to be selected for conveyors, which rriotor would be preferred ?
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A. Differentially compound motor

B. Cumulative compound motor

C. Shunt motor

D. Series motor
799. In case of a 4-pole D.C. generator provided with a two layer lap winding with sixteen coils, the pole pitch will be__________________?
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A. 8

B. 4

C. 16

D. 32

800. Where D.C. motor of H.P. 12 or more requires frequent starting, stopping, reversing and speed control______________?
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A. four point starter is used

B. drum type controller is used

C. all above can be used

D. three point starter is used