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
501. For the induced draught the fan is located_______________?
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A. near bottom of furnace

B. anywhere permissible

C. near bottom of chimney

D. at the top of the chimney

502. Pipes carrying steam are generally made up of_____________?
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A. copper

B. aluminium

C. cast iron

D. steel
503. The following system is not generally used?
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A. 1-phase 4 wire

B. 3-phase 4 wire

C. 1-phase 3 wire

D. 3-phase 3 wire

504. The isentropic expansion of steam through nozzle for the steam initially superheated at inlet is approximated by equation__________?
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A. pv = C

B. pv1A = C

C. pvls=C

D. pv1126 = C

505. The square root of the ratio of line impedance and shunt admittance is called the___________?
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A. regulation of the line

B. surge impedance of the line

C. conductance of the line

D. none of the above

506. No-load speed of which of the following motor will be highest ?
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A. Series motor

B. Shunt motor

C. Cumulative compound motor

D. Differentiate compound motor

507. Which of the following statements regarding an idel single-phase transformer having a turn ratio of 1 : 2 and drawing a current of 10 A from 200 V A.C. supply is incorrect?
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A. Its rating is 2 kVA

B. Its secondary current is 5 A

C. Its secondary voltage is 400 V

D. It is a step-up transformer

E. Its secondary current is 20 A
508. In Rankine cycle the work output from the turbine is given by__________?
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A. change of temperature between inlet and outlet

B. change of internal energy between inlet and outlet

C. change of enthaply between inlet and outlet

D. change of entropy between inlet and outlet

509. During open circuit test of a transformer:
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A. primary is supplied full-load current

B. primary is supplied rated kVA

C. primary is supplied current at reduced voltage

D. primary is supplied rated voltage
510. For which of the following equipment current rating is not necessary?
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A. Load break switch

B. Circuit breakers

C. Isolators

D. Circuit breakers and load break switches

511. Load center in a power station is___________?
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A. center of coal fields

B. center of gravity of electrical system

C. center of maximum load of equipments

512. Which of the following D.C. distribution system is the simplest and lowest in first cost ?
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A. Ring system

B. Radial system

C. Inter-connected system

D. None of the above

513. For an overhead line, the surge impedance is taken as________________?
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A. 100200 ohms

B. 7080 ohms

C. 5001000 ohms

D. none of the above

E. 20-30 ohms

514. The voltage regulation in magnetic amplifier type voltage regulator is effected by__________?
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A. varying the resistance

B. varying the reactance

C. variable transformer

D. electromagnetic induction

515. Most of the high transmission lines in Pakistan are_______________?
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A. either of the above

B. none of the above

C. underground

D. overhead
516. In a transformer the resistance between its primary and secondary should be_____________?
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A. zero

B. 1000 Q

C. infinity

D. 10 Q

517. The artificial draught normally is designed to produce____________?
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A. less chimney gas temperature

B. all of the above

C. less smoke

D. more draught

518. If the load factor of a power station is high then its cost of generation will be_______?
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A. Remain same.

B. Low.

C. High.

D. Depend upon plant type.

519. _______________are the conductors, which connect the consumers terminals to the distribution?
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A. Service mains

B. Distributors

C. Feeders

D. None of the above

520. The draught produced, for a given height of the chimney and given mean temperature of chimney gases_______________?
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A. may increase or decrease with increase in outside air temperature

B. remains the same irrespective of outside air temperature

C. increases with increase in outside air temperature

D. decreases with increase in outside air temperature
521. In a regenerative feed heating cycle, the optimum value of the fraction of steam extracted for feed heating________________?
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A. decreases with increase in Rankine cycle efficiency

B. is unaffected by increase in Rankine cycle efficiency

C. none of the above

D. increases with increase in Rankine cycle efficiency
522. The critical pressure ratio of a convergent nozzle is defined as_____________?
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A. the ratio of inlet pressure to outlet pressure of nozzle

B. the ratio of outlet pressure to inlet pressure of nozzle

C. the ratio of outlet pressure to inlet pressure only when mass flow rate = c

D. the ratio of outlet pressure to inlet pressure only when mass flow rate per unit area is minimum

523. In a regenerative feed heating cycle, the greatest economy is affected___________?
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A. when steam is extracted from several places in different stages of steam turbine

B. when steam is extracted from only one suitable point of steam turbine

C. when steam is extracted only from the last stage of steam turbine

D. when steam is extracted only from the first stage of steam turbine

524. Part of the transformer which is most subject to damage from overheating is_____________?
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A. copper winding

B. iron core

C. frame or case

D. winding insulation

E. transformer tank

525. Artificial draught is produced by______________?
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A. induced and forced fan

B. all of the above

C. induced fan

D. forced fan

526. The cooling section in the surface condenser__________?
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A. reduces the quantity of vapour extracted along with air

B. none of the above

C. increases the quantity of vapour extracted along with air

D. does not affect vapour quantity extracted but reduces pump capacity of air extraction pump

527. The operating voltage of high voltage cables is up to_______________?
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A. 3.3kV

B. l.lkV

C. llkV

D. 6.6kV

528. The operating voltage of extra high tension cables is upto_______________?
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A. 132 kV

B. 66 kV

C. 6.6 kV

D. 33 kV

E. 11 kV

529. Steam turbines commonly used in steam power station are__________?
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A. non-condensing type

B. condensing type

C. none of the above

530. Series capacitors on transmission lines are of little use when the load VAR requirement is___________?
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A. large

B. small

C. fluctuating

D. any of the above

531. The power factor of industrial loads is generally______________?
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A. unity

B. leading

C. zero

D. lagging
532. Blowing down of boiler water is the process_____________?
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A. none of the above

B. to control the solid concentration in the boiler water by removing some of the concentrated saline water

C. to increase the steam temperature

D. to reduce the boiler pressure

533. If a transformer is switched on to a voltage more than the rated voltage______________?
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A. its power factor will remain unaffected

B. its power factor will be zero

C. its power factor will increase

D. its power factor will deteriorate
534. The voltage drop, for constant voltage transmission is compensated by installing__________?
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A. none of the above

B. all of above

C. capacitors

D. synchronous motors

E. inductors

535. The function of breather in a transformer is___________?
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A. to provide oxygen inside the tank

B. to arrest flow of moisture when outside air enters the transformer

C. to cool the transformer oil

D. to cool the coils during reduced load

536. Rankine efficiency of a steam power plant____________?
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A. improves in summer as compared to that in winter

B. improves in winter as compared to that in summer

C. is unaffected by climatic conditions

D. none of the above

537. Caking coals are those which__________?
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A. burn freely

B. do not form ash

C. burn completely

D. form lumps or masses of coke
538. The modern steam turbines are___________?
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A. none of the above

B. impulse turbines

C. impulse-reaction turbines

D. reaction turbines

539. The frequency of voltage generated, in case of generators, can be increased by___________?
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A. using reactors

B. none of the above

C. increasing the load

D. adjusting the governor

E. reducing the terminal voltage

540. Which of the following application requires high starting torque ?
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A. Centrifugal pump

B. Locomotive

C. Air blower

D. Lathe machine

541. Economiser is used to heat_____________?
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A. air

B. all above

C. flue gases

D. feed water
542. When a conductor carries more current on the surface as compared to core, it is due to___________?
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A. unsymmetrical fault

B. none of the above

C. skin effect

D. corona

E. permeability variation

543. Short circuit test on transformers is conducted to determine____________?
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A. hysteresis losses

B. eddy current losses

C. core losses

D. copper losses
544. Reheat factor in steam turbines depends on______________?
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A. all of the above

B. exit pressure only

C. stage efficiency only

D. initial pressures and temperature only
545. The current drawn by the line due to corona losses is___________?
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A. square

B. sinusoidal

C. non-sinusoidal

D. triangular

546. Solar thermal power generation can be achieved by_______________?
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A. using flat plate collectors

B. using a solar pond

C. using focusing collector or heliostates

D. any of the above system
547. A good voltage regulation of a transformer means________________?
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A. difference between primary and secondary voltage is maximum

B. output voltage fluctuation with power factor is least

C. output voltage fluctuation from no load to full load is least

D. difference between primary and secondary voltage is least

E. ood voltage regulation of a transformer means

548. Which of the following is the demerit of a constant voltage transmission system ?
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A. Availability of steady voltage at all loads at the line terminals

B. Increase of short-circuit current of the system

C. Improvement of power factor at times of moderate and heavy loads

D. Possibility of carrying increased power for a given conductor size in case of long-distance heavy power transmission

E. Possibility of better protection for the line due to possible use of higher terminal reactants

549. A conductor, due to sag between two supports, takes the form of____________?
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A. triangle

B. semi-circle

C. catenary

D. ellipse

550. The amount of air which is supplied for complete combustion is called___________?
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A. secondary air

B. primary air

C. tertiary air