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Utilization of Electrical Energy

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Utilization of Electrical Energy

shape Introduction

Energy is defined as the capacity to do work. The major utilization of electrical energy is to generate output from electrical and electronics devices. Utilization of electric energy is primarily prominent in industry, domestic utilization, in commercial usage, in public service, in transport, in fishery etc.

shape Quiz

Q1. Method which is appropriate for heating non-ferrous metals?
    A. Dielectric heating B. Radiant heating C. Indirect arc heating D. Indirect resistance heating Answer: C

Q2. Methods which is suitable for the heating of conducting medium is
    A. Radiant heating B. Eddy current heating C. Induction heating D. Indirect arc heating Answer: C

Q3. Which of the following comparisons between the filament lamp and the fluorescent lamp is correct?
    A. The flurescent lamp has a higher dazzle B. The fluorescent lamp produces sharper shadows C. The fluorescent lamp produces greater brightness D. The average life of the fluorescent lamp is five to seven times higher Answer: D

Q4. Which of the following statements about illumination is true?
    A. If the distance from the source doubles, the illumination becomes half B. If the distance from the source doubles, the illumination reduces to on e fourth C. The greater the illumination, the better one sees D. The finer the work, the less the required illumination Answer: B

Q5. High frequency for induction heating can be generated by
    A. motor generator set B. spark gap oscillator C. vacuum tube oscillator D. all of these Answer: B

Q6. Flux used in TIG welding is
    A. Ammonium chloride B. Borax C. Ash D. None of these Answer: D

Q7. In Argon are welding, the electrode is made of
    A. carbon B. steel C. tungsten D. no electrode is needed Answer: C

Q8. A 10-SWG electrode has approximate diameter of
    A. 0.9 mm B. 1.2 mm C. 3.3 mm D. 10 mm Answer: C

Q9. In gas welding, the gases used are
    A. oxygen and nitrogen B. argon and helium C. helium and carbondioxide D. acetylene and oxygen Answer: D

Q10. Grey iron is usually welded by
    A. Arc welding B. Gas welding C. TIG welding D. MIG welding Answer: B
Q11. The danger of electric shock is maximum
    A. during arcing B. after arcing C. before welding D. while inserting electrode into the holder Answer: D

Q12. The transformer used for a.c. welding sets is
    A. Booster type B. Step-up transformer C. Step-down transformer D. None of these Answer: C

Q13. A welding accessory is
    A. Electrode holder B. Hand screen C. Gloves D. All of these Answer: D

Q14. For regenerative braking, the regenerated power should have
    A. the same frequency as that of the main supply B. frequency 173 of that of the main supply C. frequency 1/2 of that of the main supply D. any frequen cy Answer: A

Q15. Bearings used to support axles of rolling stock are
    A. bush bearings B. journal bearings C. ball bearings D. roller bearings Answer: D

Q16. D.C. supply can be obtained from A. C. supply by the use of
    A. motor generator set B. mercury arc rectifier C. silicon diodes D. all of these Answer: D

Q17. Ward-Leonard controlled d.c. drives are generally used for
    A. light duty excavators B. medium duty excavators C. heavy duty excavators D. all of these Answer: C

Q18. Motor used for elevators is generally
    A. synchronous motor B. induction motor C. capacitor start single-phase induction motor D. all of these Answer: B

Q19. Earth Least preferred for earthing is
    A. earth mixed with salt and charcoal B. dry earth C. mashy ground containing brine waste D. clay soil Answer: B
Q20. Miniature lamps on automobiles are used for
    A. tail lamp B. dash board lamp C. side lamp D. all of these Answer: D

Q21. The heating time constant of a totally enclosed motor is relatively
    A. higher B. lower C. indepen dent of type of en closure D. none of these Answer: A

Q22. Wound rotor and squirrel-cage motors with high slip which develop maximum torque at stand still are used for
    A. presses and punches B. machine tools C. elevators D. all of these Answer: A

Q23. Premature blowing of a fuse may occur due to
    A. heating at ferrule contacts B. corrosion or oxidation of ferrules C. weak contact pressure D. all of these Answer: D

Q24. The earthwise should not be thinner than a
    A. 18 SWG wir e B. 16 SWG wire C. 10 SWG wire D. 8 SWG wire Answer: D

Q25. Mixture preferred for filling around the earth for electrode effective earthing is
    A. bone-meat mixture B. coal-salt mixture C. saw-dust sand mixture D. lime-sand mixture Answer: B

Q26. Motor used for elevators is generally
    A. synchronous motor B. induction motor C. capacitor star single-phase induction motor D. any of these Answer: B

Q27. A locomotive exerts a tractive effort of 40,000 N in pulling a train at 60 kmph on a level track. If the same train is to be hauled at the same speed but on gradient, the tractive effort required will be 60,000 N. The output delivered by the motor will be more if it is driven by
    A. a 3-phase induction motor B. a dc series motor C. an ac series motor D. equal in all the three cases Answer: A

Q28. Wound rotor and squirrel-cage motors with high slip which develop maximum torque at stand still are used for
    A. presses and punches B. machine tools C. elevators D. all of these Answer: A

Q29. The basic elements of an electric drive are
    A. electric motor and the transmission system B. electric motor, the transmission and control system C. the transmission and control system D. electric motor and conversion equipments Answer: B

Q30. The amount of energy returned to the line during regeneration depends on
    A. the initial and final speeds during regenerative braking B. efficiency of the system C. the train resistance and gradient of track also in case the train is moving down the gradient D. all of the above Answer: B
Q31. The device necessarily used for automatic temperature control in a furnance is
    A. thermostat B. auto-transformer C. thermo-couple D. any of the above Answer: A

Q32. A single phase reluctance motor
    A. has salient pole rotor structure and runs at subsynchronous speed B. has salient pole rotor structure and runs at super- synchronous speed C. has salient pole rotor structure and runs at synchronous speed D. has not-salient pole rotor structure and runs at synchronous speed Answer: C

Q33. For 600 V d.c. line for tram cars
    A. track is connected to negative of the supply B. track is connected to positive of the supply C. track is connected to mid voltage of 300 V D. none of these Answer: A

Q34. Utilisation factor depends upon
    A. size of the room B. space height ratio of the lamps C. colour of walls/ceiling D. all of the above Answer: D

Q35. Which of the following site will be preferred for earthing?
    A. Wet mashy ground B. Clay soil C. Loam mixed with small quantities of sand D. Damp and wet sand pit Answer: A

Q36. Which of the following heating elements can give highest temperature in resistance heating?
    A. Copper B. Nickel copper C. Nichrome D. Silicon carbide Answer: D

Q37. The power factor at which the direct arc furnace operates is
    A. low lagging B. low leading C. unity D. high leading Answer: A

Q38. In Kando system of track electrification
    A. single phase a.c. is converted into d.c. B. single phase a.c. is converted into 3-phase a.c. C. 3 phase a.c. is converted into d.c. D. 3 phase a.c. is converted into single phase a.c. Answer: D

Q39. Belted slip ring induction motor is almost invariably used for
    A. centrifugal blowers B. water pumps C. jaw crushers D. heavy load Answer: C

Q40. Inside the earth or pit, the earthing electrode should be placed
    A. vertical B. horizontal C. inclined at 45° D. none of these Answer: A
Q41. Which of the following statements about illumination is true?
    A. if the distance from the source doubles, the illumination becomes half B. if the distance from the source doubles, the illumination reduces to one fourth C. The greater the illumination, the better one sees D. The finer the work, the less the required illumination Answer: B

Q42. Which of the following devices is necessarily required for automatic temperature control in a furnace?
    A. Thermocouple B. Thermostat C. Auto-transformer D. Heating elements of variable resistance material Answer: B

Q43. Nichrome wires can be safely used for heating to temperature around 1500°C. Which of the following materials for heating elements should be selectd?
    A. Eureka B. Kanthal C. Platimum molybenum, carbon compound D. Nichrome Answer: C

Q44. The dc series motor is most suitable for traction services but more particularly for urban/suburban services because
    A. dc series motors are suitable for regenerative braking B. dc series motors are capable of withstanding rapid fluctuations in supply voltage C. dc series motors are capable of developing high torque at start D. de series motors are capable of withstanding temporary interruption of supply without undue rush of current Answer: C

Q45. In a domestic baking oven, the temperature is controlled by
    A. voltage B. series-parallel operation C. thermostate D. star-delta con nections Answer: C

Q46. The diameter of a 50-SWG wire is closer to
    A. 0.0253 mm B. 0.05 mm C. 0.16 mm D. 0.52 mm Answer: A

Q47. Applied voltage across the motor terminals during starting is not reduced in case of
    A. Star-delta starting B. Rotor-resistance starting C. Auto-trans former starting D. Stator resistance starting Answer: B

Q48. The electric locomotives run faster at curved routes as compared to steam locomotives as:
    A. the centre of gravity of electric locomotive is higher than that of steam locomotive B. the centre of gravity of electric locomotive is lower than that of steam locomotive C. the speed at curved routes is independent of location of centre of gravity D. none of these Answer: B

Q49. The illumination level required for precision work is about
    A. 500-1000 lux B. 250 lux C. 100 lux D. 50 lux Answer: A

Q50. Electric traction in comparison to other traction systems has the advantage(s) of
    A. higher acceleration and braking retardation B. cleanest system and so ideally suitable for the underground and tube railways C. better speed control D. all of the above Answer: D
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