161. In an AC generator, direct current from a separate source is passed through the windings of the rotorA. -by means of slip rings and brushesB. -by means of a commutatorC. -by means of rotating bar magnetD. -to minimize the danger of arc over

ANS: A

162. A delayed-action fuse is most frequently used in which of the listed circuits?A. -lighting circuitB. -motor circuitC. -electric heater circuitD. -radar circuit

ANS: B

163. Which of the listed procedures should be carried out to prevent moisture damage to electrical apparatus during extended periods of idleness?A. -fill the motor housing with CO2 to inert the spaceB. -strap silica gel around the commutatorC. -place heat lamps in the motor housingD. -cover the equipment with a canvas tarpaulin

ANS: C

164. A fuse of recommended current and voltage ratings that blows often should be replaced only with a fuse ofA. -the same ratingsB. -higher ratingsC. -higher current and lower voltage ratingD. -lower current and higher voltage rating

ANS: A

165. Which of the listed conditions is an advantage of a PN diode over a vacuum diode?A. -longer lifeB. -no warm up timeC. -less delicateD. -all of the above

ANS: D

166. The freezing point of the electrolyte in a fully charged lead-acid battery will beA. -higher than in a discharged batteryB. -lower than in a discharged batteryC. -the same as in a discharged batteryD. -higher than in a discharged battery, but the specific gravity will be less

ANS: B

167. To repair a small electrical motor that has been submerged in saltwater, you shouldA. -wash it with fresh water and apply an external source of heatB. -renew the windingsC. -send it ashore to an approved service facilityD. -rinse all electrical parts with a carbon tetrachloride cleaning solvent and then blow dry

the motor with compressed airANS: A

168. The basic measuring unit of inductance is theA. -coulombB. -ohm

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C. -faradD. -henry

ANS: D

169. Which of the listed precautions should be taken when cleaning the internals of a motor with compressed air?A. -open the machine on both ends so as to allow the air and dust to escapeB. -be certain that the circuit breaker is opened and tagged on the feeder panelC. -be certain that the air is clean and as dry as possibleD. -all of the above

ANS: D

170. The purpose of DC generator brushes is toA. -neutralize armature reactionB. -conduct electric current to an outside circuitC. -convert DC current to AC currentD. -provide excitation to a DC generator

ANS: B

171. Fuses are rated inA. -voltageB. -amperageC. -interrupting capacityD. -all of the above

ANS: D

172. Power transformers are rated inA. -kilowattsB. -ampere-turnsC. -kilowatt-voltsD. -kilovolt-amperes

ANS: D

173. Alternative current circuits develop resistance, inductance and capacitance. The inductance of a coil is expressed inA. -ohmsB. -mhosC. -henrysD. -farads

ANS: C

174. A lead-acid battery is considered fully charged when theA. -electrolyte gasses freelyB. -battery charger ammeter indicates a positive readingC. -terminal voltage reaches a constant value at a given temperatureD. -specific gravity of all cells reaches the correct value and no longer increases over a

period of 1 to 4 hrs.ANS: D

175. The insulation resistance of electric equipment and machinery should be tested forthe lowest normal insulation valuesA. -immediately after shutting down the machineB. -every time the brush rigging is adjustedC. -immediately after starting up the machineD. -every 30 days whether the machine is in use or not

ANS: A

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176. High vacuum diodes, gas-filled diodes, and germanium semiconductor diodes may all be used asA. -potentiometersB. -rectifiersC. -power sources D. -photocells

ANS: B

177. The apparent power in a purely inductive circuit is also known asA. -true powerB. -lead powerC. -induced powerD. -reactive power

ANS: D

178. Which of the following devices will prevent a DC generator from becoming motorized? (If AC generator means Ans C)A. -overcurrent relayB. -motorization tripC. -reverse power relayD. -reverse current relay

ANS: D

179. A grounded switch or cable will be indicated by a meg ohmmeter reading ofA. -infinityB. -zeroC. -being unsteady in the high rangeD. -being unsteady in the low range

ANS: B

180. Regarding battery charging rooms, ventilation should be providedA. -at the lowest point of the roomB. -horizontally near the batteriesC. -at the highest point of the roomD. -only when charging is in progress

ANS: C

181. The main difference between an electron tube and a transistor is theA. -type of function they can performB. -reaction of electron flow through a gas or vacuum in a transistorC. -reaction of electron flow through a semiconductor when placed in a tubeD. -reaction of electron flow through a semiconductor used to form a transistor

ANS: D

182. A generator has been exposed to water and is being checked for its safe operation. Therefore, it is necessary toA. -check for shorted coils with a growlerB. -take moisture readings with a hydrometerC. -test insulation values with a meggerD. -ground the commutator, or slip rings and run it at half load for 12 hours

ANS: C

183. Before testing insulation with a meg ohmmeter, the windings of large machines should be grounded for about 15 minutes just prior to test, because theA. -static charge of the machine may give a false readingB. -armature will have a greater number of leakage pathsC. -insulation may be damagedD. -insulation may be covered with moisture

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ANS: A

184. In a DC series circuit, all the conductors have the sameA. -power expended in themB. -voltage drop across themC. -resistance to current flowD. -current passing through them

ANS: D

185. A three-phase induction-type motor experiences an open in one phase. Which of the listed automatic protective devices will prevent the machine from being damaged?A. -overspeed tripB. -thermal overload relayC. -three-pole safety switchD. -magnetic blowout coil

ANS: B

186. Most three-phase induction motors used for driving engine room auxiliaries are started byA. -resistor startersB. -across-the-line startersC. -impedance startersD. -reactor starters

ANS: B

187. When electrical cables penetrate watertight bulkheads,A. -they should be grounded on either side of the bulkheadB. -they must be bent to a radius of six diametersC. -a watertight stuffing tube capable of accepting packing should be employedD. -they should be secured by a clamp

ANS: C

188. Across-the-line starters are used with AC motors to provideA. -reduced starting currentB. -regulated starting currentC. -high starting torqueD. -controlled starting acceleration

ANS: C

189. Most conductive materials such as copper, aluminum, iron, nickelA. -increase in resistance with increased temperatureB. -increase in resistance with decreased temperatureC. -decrease in resistance with increased temperatureD. -decrease in resistance with decreased temperature

ANS: A

190. The electrician reports to you that he has obtained low (but above 1 megohm) megger readings on the windings of a deck winch motor. Upon checking the records of that motor, you find the readings have consistently been at the same level the last six years. You should, therefore, recommend that theA. -motor be replacedB. -windings be driedC. -windings be cleanedD. -readings are acceptable

ANS: D

191. Line losses in a distribution circuit are kept to a minimum byA. -adding rubber insulation conductors to the circuit

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B. -using higher current and lower voltageC. -increasing the number of thermal relays in the circuitD. -using higher voltage and lower current

ANS: D

192. Adding resistance in series with the field winding of a DC shunt motor without a load, will cause the motor speed toA. -increaseB. -decreaseC. -remain the sameD. -fluctuate rapidly

ANS: A

193. The function of the compensating windings used in a DC generator is toA. -prevent cross-commutationB. -increase armature coil strengthC. -increase field strengthD. -neutralize armature reaction

ANS: D

194. Capacitors are used on the output of the power supply in today's consoles toA. -filter out "ripple"B. -prevent overloadsC. -act as a permanent loadD. -decrease the average value of the output voltage

ANS: A

195. The purpose of a motor under voltage protection device is toA. -prevent high armature current when power is restoredB. -start the motor at a very low voltageC. -trip the load off the motor in case of fireD. -protect personnel from low voltage shocks

ANS: A

196. In testing a three-phase delta winding for an open circuit using a meg ohmmeter, you mustA. -test each phase with all connections intactB. -measure the voltage across the open connections while testingC. -test the windings as parallel groups to avoid short circuitingD. -open the delta-connections to avoid shunting the phase being tested

ANS: D

197. The direction of rotation of an induction motor isA. -opposite to the rotating field B. -the same as the direction of the rotating fieldC. -determined by the number of polesD. -determined by the staggering of the brushes

ANS: B

198. mercury filled thermometers should never be used to determine the temperature ofthe battery electrolyte because accidental breakage of the thermometer can causeA. -severe sparking and explosionsB. -rapid oxidation of battery platesC. -contamination of the electrolyteD. -corrosion on the battery terminals

ANS: A

199. The purpose of a main switchboard circuit breaker's revers-power trip is to

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A. -prevent main circuit overloadB. -protect the circuit breaker blowout coilC. -prevent alternator motorizationD. -prevent low voltage trip out

ANS: C

200. When charging lead-acid batteries, the charging rate should be reduced as the battery nears its full charge toA. -prevent damaging battery platesB. -allow equalization of cell voltagesC. -reduce lead sulfate depositsD. -increase lead peroxide formation

ANS: A

201. Regarding an induction motor, the power developed by the rotor automatically adjusts itself to A. -power required to drive the loadB. -speed required to drive the loadC. -current flow in the motor statorD. -torque developed by the rotating field

ANS: A

202. The purpose of a magnetic relay is toA. -open a circuit only in the event of overloadB. -remotely open and close contactsC. -provide overcurrent protection during startingD. -relay voltages at increased power

ANS: B

203. A semiconductor is a material with aA. -conductivity higher than a normal conductorB. -conductivity higher than a normal insulatorC. -high conductivity at low temperaturesD. -low conductivity at high temperatures

ANS: B

204. The winding resistance of a coil can be increased by _______ the number of turnsor using a ______ wire.

A. increasing, thickerB. decreasing, thickerC. increasing, thinnerD. decreasing, thinner

ANS: C

205. The most common source of excitation for synchronous motors is a/an _____________.(A) low voltage battery(B) motor attenuator set(C) DC exciter generator(D) AC supply

ANS: C

206. On an engine throttle control system, the aux control circuits are provided with devices to prevent excessive over travel of the pilot valve by the synchronous motor these devices are called.

A. overlap sensor

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B. limit switchC. over travel relayD. proximity switch

ANS: B

207. The speed of the squirrel cage induction motor is determined by A. Dia of statorB. No of stator polesC. Rotor winding resistanceD. Bar resistance of conducting rotor

ANS: B

208. The method used to produce electron emission in most vacuum tubes is known asA. Photo electric emissionB. Secondary electric emissionC. Cold cathodic electric emissionD. Thermionic emission

ANS: D

209. A reverse current relay prevents dc generator motorization automatically by option

A. Redirecting up prime mover, B. Securing the exciter generator, C. Tripping the circuit breaker.

ANS: C

210. Di electric constant of 3.6 A. WaterB. PaperC. ElectrolyteD. Air

ANS: B

211. RMS value of a sine wave current is expressed as A. Average value,B. Max valueC. Effective valueD. Instantaneous value

ANS: C

212. Which of the following statements comparing transistors and vacuum tubes is correct?A. Both transistors and vacuum tubes have a cathode that must be heated to give off electrons.B. A vacuum tube must have a heated cathode, where transistors do not.C. Neither transistors nor vacuum tubes require heat for electrons to flow.D. The anode of both transistors and vacuum tubes must be heated to give off electrons.

ANS: B

213. Electric and electro-hydraulic steering gear motors are required by Coast Guard Regulations (46 CFR) to be _________.A. protected by a circuit breaker set at 125% and a thermal overload deviceB. provided with a running motor overcurrent protection device

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C. served by a single two conductor cableD. served by two feeder circuits

ANS: D

New Questions

1. What happens to the strength of electromagnetic field when current passing through an inductor is halfed?

A. ¼B. ½C. 2D. 4

ANS: A

2. To prevent the race of DC series, motor what arrangement should make? a. Always start at heavy loadb. Use a strong series weak shunt compound DC motorc. Use a weak series strong shunt compound DC motord. All

ANS: A

3. If thyristor is used in place of starter (mcq) a. Cost decreasesb. Space decreasesc. As load increases frequency increases uniformlyd. Maintenance decreases

ANS: A B & D

4. For incoming generator which of the statements are true? a. If Incoming generator voltage is increased, then it will have motoring effect.b. If voltage is decreased, then it will cause black out.c. If frequency do not match, then it will run slowly. d. If frequency do not match, then will run fast.

ANS: B

5. Pure inductive power is called a. Reactive powerb. True powerc. Set power

ANS: A

6. Zener diode is used as a. Voltage regulatorb. Rectifier

ANS: A

7. How with the help of pressure electrical signal is converted? i. Transducerii. Tuctile sensoriii. Reactoriv. Don’t remember

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a. Only ib. I & iic. Only ivd. Ii & iv

ANS: A

8. Which statement is true in relation to AUTO TRANSFORMER? (mcq) a. More effective than conventional transformerb. Any fractional voltage can be applied c. Can be used both for A.C and D.Cd. Less excitation needed.e. LOW COSTf. SMALL SIZE

ANS: A B D E & F

9. For a turbo electric propulsion generator which can be fitted? a. Co2 systemb. Moisture somethingc. Stator winding temperature sensord. All

ANS: D

10. Class B AMPLIFIER advantage? a. Very low standing bias current.b. Negligible power consumption without signal.c. More efficient than Class A.d. Can be used for much more powerful outputs than class A

ANS: A B C & D11. How is natural cooling of transformer done?

a. Air blastb. Oil coolingc. Water coolingd. None

ANS: A

12. Atoms are bonded by? a. Valence electronsb. Neutronc. Protond. Not known

ANS: A

13. If in an electromagnetic coil current is ½ then its energy stored will be? a. ¼b. ½c. Twice d. No change

ANS: A

14. For half wave rectifier ripple factor is? (for full wave- 0.482) a. 1.41b. 1.21

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c. 131d. 1.51

ANS: B

15. To satisfy amplification, transistor amplifier must satisfy? a. Forward biasing of output circuit.b. Reverse biasing in input circuit.c. Operate at set pointd. All

ANS: C

16. Which of the following are true for Thermistors (mcq)

a. Thermistors are semiconductors devicesb. In a Positive temperature coefficient (PTC) thermistors, resistance increases with

temperature increasec. –ve temperature coefficient (NTC) thermistors, can be used as replacement of fuse.d. PTC thermistors can be used as resistance thermometers in low temperature environments. e. NTC thermistors are generally used for monitoring coolant and engine lube oil temp in

automobiles.

ANS: A B & E

17. Which trip is present in emergency generator? a. Over voltage tripb. Under voltage tripc. Over speed trip d. None

ANS: C

18. NER- what is true for high voltage circuit? a. To limit max load currentb. Neutral earth resonancec. Main switchboard earthedd. Not known

ANS: A

19. Which of the following is not self-starting motor? a. Squirrel cage motorb. Synchronous motorc. Induction motord. Split phase motor

ANS: B

20. In capacitor, energy stored is? SURE a. Potential energyb. Electrostatic energyc. Kineticd. Not known

ANS: B

21. For t/c, leak current in P-N diode is produced by?

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a. Heat energyb. Chemical energyc. Barrier potentiald. Not known

ANS: A

22. Motor overhaul is to be done which statements are true?a. Stator should be isolatedb. Tag on overall shipc. Not known

ANS: A

23. Electric motor stator- true statements? (mcq) a. Generator used only with slip rings motors.b. Freq. convertor can be used as starter.c. Auto transformer act as rheostat starterd. Not known

ANS: B & C

24. Limit switch àE/n throttle ---> limits pilot v/v moment

25. Squirrel cage used in synchronous motor for? a. Improving p.fb. Uniform balancingc. Just for startingd. Not known

ANS: C

26. Which of the following will prevent a DC generator from becoming motorized? a. Overcurrent relayb. Motorization tripc. Reverse power relayd. Reverse current relay

ANS: D

27. For leading power circuits which of the following can be used? a. Shunt capacitors onlyb. Shunt reactors onlyc. Either shunt capacitors or shunt reactorsd. Neither shunt capacitors nor shunt reactors

ANS: B

28. To repair a small electric motor which was submerged in saltwater, you should a. Wash it with f.w and apply an external source of heat.b. Renew the windingsc. Send to ashore to an approved service facilityd. Rinse all electrical parts with a carbon tetrachloride cleaning solvents and then blow dry

the motor with compressed air

ANS: A

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29. An operating characteristic appearing on the name plates of shipboard AC motor is ___________

a. Type of windingsb. Input kwc. Temp rised. Locked rotor torque

ANS: C

30. Fuses replaced in series with thermal trip type ckt breakers are used for? a. Time delay protection b. Short ckt protection c. Short duration surge protection d. Sustained overload protection

ANS: B

31. To prevent the race of DC series, motor what arrangement should make? e. Always start at heavy loadf. Use a strong series weak shunt compound DC motorg. Use a weak series strong shunt compound DC motorh. All

ANS: A

32. Current applied to lead acid battery would lead to a. Higher thermal voltageb. Lower terminal voltage high chargingc. Increase generation of H2 gasd. Decrease in specific gravity of electrolyte

ANS: C

33. Across the line starters are used with AC motors to provide a. Reduced starting currentb. Regulated starting currentc. High starting torqued. Controlled starting acceleration

ANS: C

34. In an earth neutral system, an earth fault will occur onlya. 1 fault in 1 lineb. 2 fault in two line c. Two fault in 1 lined. Don’t know

ANS: A

35. Which statement is true for any storage battery a. Amp hr. efficiency of alkaline battery is high than lead acid batteryb. Watt hr. efficiency of alkaline is more than lead acid batteryc. Alkaline battery can left in any state of charge or discharged. All

ANS: C

36. Which of the following is true about star delta starters (mcq)

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a. Popular bcoz relatively inexpensiveb. Gives lower starting current than DOLc. Can only be used with induction motor delta connected in supply voltaged. Typically used to start the motor with lower voltage

ANS: B C & D

37. Which of the following are true for shipboard storage batteries? a. Construction should be so as to prevent emission of sprayb. If voltage is above 200v insulation stands must be usedc. The deck below the cells should be protected with acid resisting or alkaline resisting

materials d. Battery banks above 2 kw should be kept in battery room onlye. Emgy batteries should never be stored in battery room

ANS: A C & D

38. In common collector transistor collector amplifier voltage gain a. Cannot exceed unityb. Depends on output impedancec. Depends on output signal d. Always constant

ANS: A

39. Which statement is true for reactor starter for electrical motor a. Minimal reduction in starting torque availableb. Starting current is limited in proportion to voltagec. Advantage of this method is its low cost in comparison to other startersd. In reactor starter, a Coil with iron core is connected in parallel with motor during starting

ANS: B & C

40. Which statement is true about any soft starters used in electrical motor a. Soft starters are based on semiconductorsb. Used to control the stopping of motorc. Use of soft starters initially result in lower motor torqued. Soft starters progressively increase motor voltage with causing torque or current peak

ANS: A B & C

41. Voltage generator by most AC generators is fed from the machine to the bus by means of

a. Brushes on commutatorb. Brushes on slip ringsc. Slip rings on commutatord. Direct connection from stator

ANS: D

42. Which of the following are true about a temp measuring ckt employed in in a data logger system?

1. A Wheatstone bridge can be used in conjunction with a Wheatstone bridge induction thermometer

2. Thermometer is energized using a constant current source and voltage developed is measured in potentiometer type method

3. Inductance of thermometer will change with change in tempa. 1 only

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b. 2 onlyc. 1 & 2 onlyd. 1 & 3 onlye. 2 & 3 only

ANS: D

43. Dis advantage of ward Leonard system (mcq) a. Motor generator set requires lot of spaceb. Overall efficiency of the system is low especially when lightly loadedc. System operates in very narrow speed ranged. Requires high maintenancee. Speed regulation is difficult to achieve as motor acceleration is uniform f. expensive

ANS: A B D & F

44. Which of the following are benefits of modifying ward Leonard control system by replacing motor set with a thyristor speed controller

a. Enhanced speed regulation by making the motor acceleration uniform b. Increases efficiency of system especially lightly loadedc. Reduces the overall cost d. Reduces system maintenance e. Increases operating speed range of systemf. Reduces overall space required

ANS: B C D & F

45. Arrange the following in correct sequence foe achieving correct KW sharing when an ACgenerator is paralleled with live bus bar and generator has some owe factor as others insystem

1. Synchronize the incoming generator in terms of voltage, frequency and phase.2. Trim voltage of the machine which has/ have lower load current to increase excitation3. Increase speed on incoming machine while lowering than that of others connected to

system4. Adjust machine voltage to keep overall system efficiency ready.5. Adjust the governor control switch on main switch board to increase the fuel to its prime

mover a. Adcb. Aebcc. Aecbd. Aece. Adbcf. Acbd

ANS: D

46. which of the following is true for syncronoscope (mcq) a. one of the coil in the armature is fed through a capacitor while other is through resistanceb. the coil produces a three phase rotating fieldc. the rotating armature has two coils windings perpendicular to each other.d. The field produces by the coils rotates the magnetic armature pointer at a speed relative

to the frequency of the bus bar supplye. The coils produce a single phase rotating field.

ANS: C D &E

47. Which of the following are TRUE with regards to a Synchro scope? (MCQ)

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A. One of the coils in the armature is fed through an Inductor while the other is fed through a Resistor.

B. The rotating armature has two coil windings parallel to each other.C. The coils produce a two-phase rotating field.D. One of the coils in the armature is fed through a Capacitor while the other is fed through

an Inductor.E. The field produced by the coils rotates the magnetic armature pointer at a speed relative

to the voltage of the bus-bar supply.

ANS: A Only

48. Which of the following are TRUE with regards to incorrect synchronization of Alternators?

a. If incoming supply voltage is higher than that of bus bar, the alternator will start drawing power from bus bar and start motoring.

b. If incoming supply voltage is lesser than that of bus bar, the alternator will start drawing power from bus bar and start motoring.

c. If frequencies of bus bar and alternator don???t match, alternator will run on low frequency on synchronization.

d. If frequencies of bus bar and alternator don???t match, alternator will run on high frequency on synchronization.

e. If voltages are not in phase and circuit breaker is closed, the phase difference will cause overloading and potential black out.

f. If voltages are not in phase and circuit breaker is closed, the phase difference will cause low current to flow from alternator and alternator will run on low load.

ANS: B & E

49. Motor having rheostat in motor circuit to vary speed in cell a. Squirrel cage motorb. Regenerating breaker motorc. Wound round induction motord. Synchronous motor

ANS: C

50. Mercury filled thermometer should never be used to determine the temp of the battery electrolyte bcoz accidental breakage of thermometer can cause

a. Severe sparking and explosionsb. Rapid oxidation of battery platesc. Contamination of the electrolyted. Corrosion of battery terminals

ANS: A

51. An amplifier is said to suffer distortion when its output is a. Lowb. Different from inputc. Noisyd. Larger than is input

ANS: B

52. What happens when battery is excess charged?

A. Electrolyte decreasesB. Gassing increasesC. Don’t remember

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D. Don’t remember

ANS: B

53. Which statements are true of starts used for electric motor. Mcq a. Rheostat starting can be used with slip ring motorsb. Frequency convertor cannot be used as statorc. Soft stator is made of semiconductord. Advantage of Reactor start is their relatively low cost

ANS: A C & D

54. Max full wave rectifier efficiency possible by two diodes from a sinusoidal wave is (Half wave is 40.6%)

a. 80.2b. B.82.1c. C.81.2d. None of the above

ANS: C

55. An amplifier is said to suffer from distortion when its output is a. Lowb. Different from inputc. Noisyd. Larger than is input

ANS: B

56. Common emitter amplifier is characterized by a. Low voltage gainb. Moderate power gainc. Signal phase reversald. Very high output impedance

ANS: C

57. The depletion region in semiconductor diode is due to a. Reverse biasingb. Forward biasingc. Crystal dopingd. Migration of mobile charge carriers

ANS: D

58. Which statement is true for any storage battery

a. Amp hr. efficiency of alkaline battery is high than lead acid batteryb. Watt hr. efficiency of alkaline is more than lead acid batteryc. Alkaline battery can left in any state of charge or discharged. All

ANS: C

59. Which of the following does not change in a transformer? SURE a. Currentb. Voltagec. Frequency

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ANS: CReversing any two of the three rotor leads on induction motor will _____________.

a. increase motor performanceb. decrease motor performancec. reverse the motord. have no effect on the direction of rotation or motor performance

ANS: C60. Which of the following statements represents an application of a silicon controlled

rectifier? A. To provide DC power for a main propulsion motor. B. For use as a voltage reference diode.C. For sensing flame in an automated burner. D. To eliminate power supply hum.

ANS: A

61. Motor having rheostat in motor circuit to vary speed in cell a. Squirrel cage motorb. Regenerating breaker motorc. Wound round induction motord. Synchronous motor

ANS: C62. Which of the following method used for biasing a BJT in integrated circuits is considered

independent of transistor beta? A. Fixed biasing

B. Voltage divider bias

C. Collector feedback bias

D. Base bias with collector feedback

ANS: B63. Large cable sizes are formed as individual conductors that may be comprised of several

smaller strands to

a. obtain the flexibility required for easy handling b. reduce the overall weight of the wire run

c. reduce the number of supports needed for a horizontal overhead run

d. all of the above

ANS: A64. Which of the following are TRUE with regards to a Synchro scope?

a. One of the coils in the armature is fed through a Capacitor while the other is fed through a Resistor.

b. The coils produce a three-phase rotating field.

c. The rotating armature has two coil windings perpendicular to each other.

d. The field produced by the coils rotates the magnetic armature pointer at a speed relativeto the frequency of the bus-bar supply.

e. The coils produce a single-phase rotating field

ANS: C D & E

65. Which of the following are TRUE with regards to incorrect synchronization of Alternators?

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a. If incoming supply voltage is higher than that of bus bar, the alternator will start drawing power from bus bar and start motoring.

b. If incoming supply voltage is lesser than that of bus bar, the alternator will start drawingpower from bus bar and start motoring.

c. If frequencies of bus bar and alternator don???t match, alternator will run on low frequency on synchronization.

d. If frequencies of bus bar and alternator don???t match, alternator will run on high frequency on synchronization.

e. If voltages are not in phase and circuit breaker is closed, the phase difference will causeoverloading and potential black out.

f. If voltages are not in phase and circuit breaker is closed, the phase difference will causelow current to flow from alternator and alternator will run on low load.

ANS: B & E

66. The main use of a Class-C amplifier is

a. as an RF amplifierb. as stereo amplifierc. in communication sound equipmentd. as distortion generator

ANS: A

67. Generator paralleling  A. Incoming generator freq is less than bus bar frequencyB. Incoming generator frequency is greater than

ANS: B68. Which of the following is/are necessary precaution(s) for paralleling an AC Generator

with live bus bars? I. Generator frequency should be close to but slightly lower than bus bar frequencyII. Generator voltage should be equal to bus bar voltageIII. Current in generator circuit should be less than bus bar current IV. Generator voltage should be in phase with bus bar voltage

A. I, II, III and IV

B.I, II and IV

C. I, II and III

D. II and IV only

ANS: D

69. In common collector transistor collector amplifier voltage gain  a. Cannot exceed unityb. Depends on output impedancec. Depends on output signal d. Always constant

ANS: A70. The main use of a Class-C amplifier is

A. as an RF amplifierB. as stereo amplifierC. in communication sound equipmentD. as distortion generator

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ANS: A

71. NER- what is true for high voltage circuit? a. To limit max load currentb. Neutral earth resonancec. Main switchboard earthedd. Not known

ANS: A72. Which statement is true in relation to AUTO TRANSFORMER? (mcq)

a. More effective than conventional transformer

b. Any fractional voltage can be applied

c. Can be used both for A.C and D.C

d. Less excitation needed.

e. Voltage regulation of autotransformer is much better

f. Its size is relatively very smaller.

ANS: A B D E & F73. For a given line voltage, four heating coils will produce maximum heat when connected

in

a. parallel b. seriesc. same heat in both the timed. none of the above

ANS: A

74. ACB trips at what condition a. reverse currentb. short circuitc. overloadd. low voltage fault

ANS: C

75. With regards to AVR which all statements are true? a. A typical AVR circuit needs two Zener diode, two resistances, one inductor, one

capacitor, one transformer and one Diode Bridge. b. The function of the transformer in an AVR is to step down the AC supply coming from

the generator terminals and feed this supply to the LC circuit. c. The function of the LC circuit in an AVR is to convert the AC supply coming from the

generator terminals into a DC supply. d. Zener diodes are typically used as voltage reference in most modern AVR. e. The function of Diode Bridge is to rectify the signal coming from the LC circuit and apply this

to the reference bridge. f. The function of the LC circuit in an AVR is to smooth the signal coming from the diode bridge

and apply this to the reference bridge.

ANS: A D & F

76. Which of the following statement is false for lead acid battery? a. when discharge both positive and negative plate contain lead sulphateb. when charged negative plate contain spongy leadc. when charged positive plate lead per oxide

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d. when discharge electrolyte undergoes no chemical reaction

ANS: D77. which of the following prevents moisture condensation in a weather deck switch board

SURE 1.installing light bulb in pedestal stand2.coat internal of switch box With epoxy sealed3.venting the switchboard regularly.4 using strip heater

a. 2 and 4b. only 4 c. 1,2,3,4 d. 3 and 2

ANS: B

78. TRUE About Battery storage a. Prevention of electrolyte spillageb. Easy accessible from top for maintenancec. But kept on wood or trayd. Alkaline and lead acid battery are kept in a separate roome. But banks more than 2kw kept in proper cover

ANS: A B C D & E

79. Which of the following is true with regards to use regenerative braking in a reversible pole change multispeed type AC induction motor? (Multiple choice question)

a. Regenerative braking is used in conjunction with the friction padb. regenerative braking is used as four quadrant controlc. . A motor in one direction can act as generator by reversing its direction through a

controllerd. this method returns converts some of the kinetic energy back into chemical energy and

feeds into the power supply.e. the power supply needs to be disconnected when motor comes to rest or the motor will turn in

opposite direction.

ANS: A C D & E

80. Transformer having laminated core? a. Temp reduceb. Reduce power factorc. Reduce eddy currentd. all of the above

ANS: C

81. For faithful amplification, a transistor must : A. Input forward biasedB. Output reverse biasedC. Work in operating pointD. All of above

ANS: D

82. Class A amplifier coupled with transformer what will be efficiency A)50 B)78.5

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ANS: A

83. Which allow to equalize power factor of two alternator A.governorB.automatic voltage regulatorC.syncroscope

ANS: B

84. When tow generators are running in parallel and field of one of them is weakened too much then it will  SUREa) deliver large share of the total load(b) deliver small share of the total load(c) run in the opposite direction(d) run as a motor in the same direction

ANS: D

85. Which of the following are true about a temp measuring ckt employed in in a data logger system 1. A Wheatstone bridge can be used in conjunction with a Wheatstone bridge induction thermometer2. Thermometer is energized using a constant current source and voltage developed is measured in potentiometer type method 3. Inductance of thermometer will change with change in temp

a. 1 onlyb. 2 onlyc. 1 & 2 onlyd. 1 & 3 onlye. 2 & 3 only

ANS: D

86. The basic control action of a magnetic amplifier depends upon _____________. (a) Variations in the load capacitance (b) changes in inductance(c) type of core material (d) construction of the core

ANS: B

87. which of the following is true for syncronoscope (mcq) A. one of the coil in the armature is fed through a capacitor while other is through resistanceB. the coil produces a three phase rotating fieldC. the rotating armature has two coils windings perpendicular to each other.D. The field produces by the coils rotates the magnetic armature pointer at a speed relativeto the frequency of the bus bar supplyE. The coils produce a single phase rotating field.

ANS: C D & E

88. Which of the following is true regarding distribution system on tankers? 

a. High voltage distribution system not allowed on tankers

b. Earthed neutral system used.

c. 3.3kv above insulated neutral system used fwd of the engine room bulkhead 

d. none of the above

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ANS: C

89. Which of the following is/are necessary precaution(s) for paralleling an AC Generator with live bus bars? I. Generator frequency should be close to but slightly lower than bus bar frequencyII. Generator voltage should be equal to bus bar voltageIII. Current in generator circuit should be less than bus bar current IV. Generator voltage should be in phase with bus bar voltage

A. I, II, III and IVB.I, II and IVC. I, II and IIID. II and IV only

ANS: D

90. BJT transistor used as an amplifier it operates in a.cut offb.well saturationc.well in saturationd. active region

ANS: D

91. ambient temperature rise in transistor a. life lossb.life increasesc.stable

ANS: A

92. fuse materialsANS: Lead, Tin, Zinc, Silver, Aluminum, Copper, Antimony

93. the amount of current needed for full protection in case of iccp system for a particular ship will be most affected by

a. wetted surface areab.quality and condition of protection pain coatingc.speed of the shipd.sea water temperature

ANS: A B C & D

94. which of the following consider to be the safest protection from static electricity discharge when connecting or disconnecting cargo hose and metal arms?

a.insulatiing flange on the length of the non-conducting hoseb.switching off ICCPc.ship shore bonding cabled.non of this above

ANS: C (Add A for MCQ)

95. Class A amplifier percentage? a. 78.8%b.50%c.25%d.75%

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ANS: C

96. In properly biased npn transistor most free electron from emitter

a. recombine with hole and base

b. recombine with emitter itself

c. stopped with emitter itself

d. pass through the base to collector

ANS: D

97. which of the following true regards to syncronoscope SUREa. the coil produce 3 phase rotating fieldb.the coil produce a 2 phase rotating fieldc.the coil produce 1 phase rotating fieldd. the rotating armature has 2 coil winding perpendicular to each othere.the rotating armature has coil parallel to each other

ANS: C & D

98. Characteristic of laser light

a. Coherent

b. Collimated

c. Monochromatic

d. all the above

ANS: D

99. which of the following used in earth neutral system a.netural earthing resistor'b.fusec.overcurrentd.transformer

ANS: A

100. 3 phase insulated earth system one of the path contact with hull a.earthedb.short crt or groundedc. a and bd.none of the above

ANS: A

101. which of the device protect the generator over load a. relay on switchb.governorc.ACBd.overspeed trip on prime mover

ANS: D

102. which is true

a. over current relay act faster than Fuse

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b. over current relay trip the contactor on over load depend on over load setting

c. fuse meant for protection against over load upto staled current

d. none of these above

ANS: B

103. n type semiconductor doping substance a.antomyb.phosporsc.arsecnicd.all the above

ANS: D

104. class B amplifier outputa.distroation freeb.out put of full wave rectifierc. output of half wave rectifier

ANS: C

Note: output is positive half cycle

105. while doping the semiconductor is adding impurities, why it is called impurities a.it change the crystal structure of the semiconductorb.it change the chemical free semiconductorc.it prevent the flow of free electrons

ANS: A

106. wound rotor motor changing the speed torque characteristic control and speed control purpose

a. use AVR with motor

b. use changing no of poles in a motor

c. use external resistor in a rotor circuit

d. use external resistor in a stator circuit

e. thyristor in combine with motor.

ANS: C

107. Ground occur in the electrical machinery as a result of insulation failure.

a. deteration through moisture

b. excessive heat

c. external period of vibration

d. all of the above

ANS: D

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108. Unique feature of a cc transistor amplifier circuit is

a. step up the impedance level

b. dose not increase the signal voltage

c. act as an impedance matching device

d. all of the above

ANS: D

109. capacitor and resistor connected in series with the sine wave generator frequency is set so that the capacitor reactance is equal to the resistance and thus equal amount of voltage appears across each component, what happen when frequency. What happens if the frequency is increased?

a. Voltage across the resistor became higher than voltage in the capacitor

b. voltage across the capacitor became higher than voltage in the resistor

c. voltage across capacitor remain same as the voltage across the resistor

d. cannot determine

ANS: A

110. Advantage of nickel cadmium battery

a. high voltage

b. fewer cell needed for same voltage

c. full charge for long time

d. less expensive

ANS: C

111. 3 phase, if it is connected insulated neutral earth system to the ship hull short crt

a. earth fault

b. both a and b

c. neither a or b

ANS: A

112. 3 phase, if it is connected insulated earth system to the ship hull

a. short crt

b. earth fault

c. both a and b

d. neither a or b

ANS: B

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113. What will be in motor, for electro steering gear?

a. Fuse

b. overload Alarm

c. overload trip

d. power failure alarm

ANS: D

114. impurities in semiconductor

a. doping

b. biasing

c. alloying

d. none of the above

ANS: A

115. Capacitor banks are connected with ac induction motor A.in parallel.B.in series.C.not connected at]D.can be connected either way –series / parallel.

ANS: A

116. A control action which produces a corrective signal relative to the length of time the controlled variable has been away from the set point, is known as

a. Integral action

b. Proportional action

c. Rate action

d. Derivative action

ANS: A

117. What happens to the amount of energy stored in the electromagnetic field when the current through an inductor is cut in half?

a. Is reduced to one fourth

b. Is reduced to one half

c. Doubles

d. Quadruples

ANS: A

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118. Doping materials are called impurities because they

a. Decrease the number of charge carriers

b. Change the chemical properties of semiconductors

c. Make semiconductors less than 100& pure

d. Alter the crystal structures of pure semiconductors

ANS: D

119. The output of class B amplifier

a. Is distortion free

b. Consists of positive half cycle only

c. Is like the output of a full wave rectifier

d. Comprises short duration current pulses

ANS: B

120. Which of the following are not appropriate precautions to be taken prior to the overhaul of the motor on a ship?

i. Prove dead at starter / motor terminals

ii. Post caution signs all over the ship

iii. Make sure work area is clear

iv. Remove overload relay

v. Isolate the motor

vi. Remove motor fuses

A. iv and vi

B. i and ii

C. i and v

D. ii and iv

E. iii and vi

ANS: D

121. What is residual magnetism?

a. Magnetism in a solenoid coil

b. Magnetism in a natural magnet

c. Magnetism remaining after magnetic field is removed

d. None of the above

ANS: C

122. Which of the following is / are true about earthing of high voltage installations?

a. High voltage installations should not be earthed at the star point of the generator

b. Neutral earthing resonance can be used for earthing high voltage installations

c. The value of the NER is usually selected to limit current to the full load current value

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d. NERs can be substituted with earthing arrangements at circuit breakers in high voltage installations to achieve the same effect

ANS: B & C

123. The circuit efficiency of a class A amplifier can be increased by using

a. Low DC power input

b. Direct coupled load

c. Low rating transistor

d. Transformer coupled load

ANS: D

124. The negative plate of a nickel cadmium battery after discharge consists of __________

a. Nickel hydroxide

b. Cadmium hydroxide

c. Potassium hydroxide

d. Cadmium

ANS: B

125. Which of the following is / are true about regulation concerning shipboard storagebatteries?

a. Construction should always be so as to prevent emission of spray

b. If voltage is above 220 V, insulation stands must be used

c. The deck below the cells should be protected with acid resisting or alkaline resisting material

d. Battery banks above 2KW should be kept in the battery room

e. Emergency batteries should never be stored in the battery room

ANS: A C & D

126. Which of the following are TRUE with regards to Bi-metal strips? (MCQ)a. Bi-metal strips are generally used for temperature sensingb. During higher than normal current flows, the bi-metal strip will bendc. Bi-metal strips are generally used for voltage regulations d. Bi-metal strips are generally used as thermal elements in an over current protection

relaye. Bi-metal strips are generally used for power control

ANS: A B C & D

127. Which of the following system is normally used in high voltage (3.3 KV and above) generation and primary distribution?

a. AC single phase two wire insulated

b. AC three phase three wire insulated

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c. DC two wire insulated

d. AC three phase three wire, neutral earthed

ANS: D

128. Which of the following protection devices are not provided for motors used in operation of electro hydraulic steering gears?

a. Fuses

b. Overload alarm

c. Overload trip

d. Power failure alarm

ANS: C

129. Which of the listed devices may be installed on a large turbo electric alternating current propulsion generator?

I. Temperature detector coils inserted in the stator slots for measuring stator temperature

II. Electric space heaters to prevent condensation of moisture

III. A CO2 fire extinguishing system

A. I, II and III

B. I and II

C. II and III

D. III only

E. I and III

ANS: A

130. The depletion region in semiconductor diode is due to

a. Reverse biasing

b. Forward biasing

c. Crystal doping

d. Migration of mobile charge carriers

ANS: D

131. Which of the following statement is false?

a. An insulated distribution system needs two earth faults on two different lines to cause a earth fault current

b. An earthed distribution system requires only one earth fault on one line to cause aearth fault current

c. An insulated system is more effective in maintaining continuity of supply to electrical equipment

d. None of the above

ANS: D

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132. Current flow in a semiconductor depends on the phenomenon of

a. Drift

b. Diffusion

c. Recombination

d. All of the above

ANS: D

133. The purpose of a cage rotor winding placed on the rotor of a synchronous motor is to

a. Provide excitation to the DC field

b. Start the machine as induction motor

c. Contribute extra torque at synchronous speed

d. Prevent the machine from falling out of step

ANS: B

134. Which of the following is / are true of starters used for electric motors?

a. Capacitor start can be used only with slip ring motors

b. Rheostat starters are based on semiconductor

c. Frequency converters can also be used as starters

d. The effect of an auto transformer start is similar to that of reactor start

ANS: C & D

135. A LED emits visible light when its ___________

a. PN junction is reverse biased

b. Depletion region widens

c. Holes and electrons recombine

d. PN junction becomes hot

ANS: C

136. Which of the following can cause “Grounds” occurring in electrical machinery as a result of insulation failure?

I. Deterioration through extended use

II. Excessive heat

III. Operating in extremely cold conditions

IV. Extended periods of vibration

A. I and II only

B. II and IV only

C. I, II and III

D. I, II and IV

E. I, II, III and IV

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ANS: E

137. For faithful amplification, a transistor must

a. Input forward biased

b. Output reverse biased

c. Work in operating point

d. All of the above

ANS: D

138. In a system of standby synchronizing lamps fitted in conjunction with a synchronoscope to synchronize an AC Generator

Lamp #1 is connected between S line of live bus bars and S line of incoming alternator,Lamp #2 is connected between R line of live bus bars and T line of incoming alternator,Lamp #3 is connected between T line of live bus bars and R line of incoming alternator.

Which of the following is the right trigger for choosing the circuit breaker?A. When lamp #1 is dark and lamp #2 and #3 are equally brightB. When lamp #1 is dark, lamp #2 is low in brightness and lamp #3 is very brightC. When all three lamps are equally brightD. When all three lamps are dark

ANS: A

139. Proper storage battery maintenance would include a. Maintaining a high charging current at all timesb. Maintaining connections tightc. Checking weight of batteries from time to timed. All of the above

ANS: B

140. The circuit efficiency of a class A amplifier can be increased by using a. Low dc power input b. Direct coupled loadc. Low rating transistord. Transformer coupled load

ANS: D

141. Maximum reverse voltage that can be applied to the PN Junction without damage is termed as: -

a. Reverse bias voltageb. Peak inverse voltagec. Breakdown voltaged. Zener voltage

ANS: B

142. The width of the depletion layer of a PN Junction a. Decreases with light dopingb. Increases with heavy dopingc. Is independent of supply voltaged. Is increased under reverse bias

ANS: D

143. Power transformers are rated in

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a) kilowattsb) ampere-turnsc) kilowatt-voltsd) kilovolt-amperes

ANS: D

144. The purpose of a main switchboard circuit breakers reverse-power trip is toa) prevent main circuit overloadb) protect the circuit breaker blowout coilc) prevent alternator motorizationd) prevent low voltage trip out

ANS: C

145. The charge of an alkaline battery is determined with a—a) hydrometerb) ammeterc) voltmeterd) hygrometer

ANS: C

146. If the pointer fails to come back to zero when the megger is not in use it means—a) the megger is out of calibrationb) this is normalc) the hairsprings are burnt outd) the pointer is stuck

ANS: B

147. the power factor of an induction motor operating at full load is-a) leadingb) laggingc) unityd) no change

ANS: B

148. In a 3 phase delta connection, the line current will be the product of phase current anda) 1.501b) 2.216c) 1.414d) 1.732

ANS: D

149. The principal difference between a 3 phase squirrel cage induction motor and a single phase induction motor is-

a) one is a split phase motor using a capacitor, while the other uses an inductorb) one has a revolving field which drags the rotor slightly behind it, while the other runs in step.c) there is no difference

d) one needs DC excitation, the other need no excitation

ANS: A

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