FUNCTION -5 (ELECTRICAL)

61. Motor having rheostat in motor circuit to vary speed in cell
    1. Squirrel cage motor
    2. Regenerating breaker motor
    3. Wound round induction motor
    4. Synchronous motor

ANS.: C

62. Which of the following method used for biasing a BJT in integrated circuits is considered independent of transistor beta?
    1. Fixed biasing
    2. Voltage divider bias
    3. Collector feedback bias
    4. Base bias with collector feedback

ANS.: B

63. Large cable sizes are formed as individual conductors that may be comprised of several smaller strands to
    1. obtain the flexibility required for easy handling
    2. reduce the overall weight of the wire run
    3. reduce the number of supports needed for a horizontal overhead run
    4. all of the above

ANS.: A

64. Which of the following are TRUE with regards to a Synchroscope?
    1. One of the coils in the armature is fed through a Capacitor while the other is fed through a Resistor.
    2. The coils produce a three-phase rotating field.
    3. The rotating armature has two coil windings perpendicular to each other.
    4. The field produced by the coils rotates the magnetic armature pointer at a speed relative to the frequency of the bus-bar supply.

ANS.: C,D

65. Which of the following are TRUE with regards to incorrect synchronization of Alternators?
    1. If incoming supply voltage is higher than that of bus bar, the alternator will start drawing power from bus bar and start motoring.
    2. If incoming supply voltage is lesser than that of bus bar, the alternator will start drawing power from bus bar and start motoring.
    3. If frequencies of bus bar and alternator don’t match, alternator will run on low frequency on synchronization.
    4. If frequencies of bus bar and alternator don’t match, alternator will run on high frequency on synchronization.

ANS.: B

66. The main use of a Class-C amplifier is
    1. as an RF amplifier
    2. as stereo amplifier
    3. in communication sound equipment
    4. as distortion generator

ANS.: A

68. Which of the following is/are necessary precaution(s) for paralleling an AC Generator with live bus bars?

1. Generator frequency should be close to but slightly lower than bus bar frequency
2. Generator voltage should be equal to bus bar voltage
3. Current in generator circuit should be less than bus bar current
4. Generator voltage should be in phase with bus bar voltage

1. I, II, III and IV
2. I, II and IV
3. I, II and III
4. II and IV only

ANS.: D

69. In common collector transistor collector amplifier voltage gain
    1. Cannot exceed unity
    2. Depends on output impedance
    3. Depends on output signal
    4. Always constant

ANS.: A

70. The main use of a Class-C amplifier is
    1. as an RF amplifier
    2. as stereo amplifier
    3. in communication sound equipment
    4. as distortion generator

ANS.: A

71. NER- what is true for high voltage circuit?
    1. To limit max load current
    2. Neutral earth resonance
    3. Main switchboard earthed
    4. Not known

ANS.: A

73. For a given line voltage, four heating coils will produce maximum heat when connected in
    1. parallel
    2. series
    3. same heat in both the time
    4. none of the above

ANS.: A

74. ACB trips at what condition
    1. reverse current
    2. short circuit
    3. overload
    4. low voltage fault

ANS.: C

75. With regards to AVR which all statements are true?
    1. A typical AVR circuit needs two zener diode, two resistances, one inductor, one capacitor, one transformer and one Diode Bridge.
    2. 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.
    3. The function of the LC circuit in an AVR is to convert the AC supply coming from the generator terminals into a DC supply.
    4. Zener diodes are typically used as voltage reference in most modern AVR.

ANS.: A,D

76. With regards to AVR which all statements are true?
    1. Zener diodes are typically used as voltage reference in most modern AVR.
    2. The function of Diode Bridge is to rectify the signal coming from the LC circuit and apply this to the reference bridge.
    3. 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.
    4. The function of the LC circuit in an AVR is to convert the AC supply coming from the generator terminals into a DC supply.

ANS.: A,C

76. Which of the following statement is false for lead acid battery?
    1. when discharge both positive and negative plate contain lead sulphate
    2. when charged negative plate contain spongy lead
    3. when charged positive plate lead per oxide
    4. when discharge electrolyte undergoes no chemical reaction

ANS.: D

77. Which of the following prevents moisture condensation in a weather deck switch board
    1. installing light bulb in pedestal stand
    2. coat internal of switch box With epoxy sealed
    3. venting the switchboard regularly.
    4. using strip heater

1. 2 and 4
2. only 4
3. 1,2,3,4
4. 3 and 2

ANS.: B

78. TRUE about Battery storage
    1. Prevention of electrolyte spillage
    2. But kept on wood or tray
    3. Alkaline and lead acid battery are kept in a separate room
    4. But banks more than 2kw kept in proper cover

ANS.: 1,2,3,4

79. Which of the following is true with regards to use regenerative braking in a reversible pole change multispeed type AC induction motor?
    1. Regenerative braking is used in conjunction with the friction pad
    2. regenerative braking is used as four quadrant control
    3. A motor in one direction can act as generator by reversing its direction through a controller
    4. this method returns converts some of the kinetic energy back into chemical energy and feeds into the power supply.

ANS.: 1,3,4

80. Transformer having laminated core?
    1. Temp reduce
    2. Reduce power factor
    3. Reduce eddy current
    4. all of the above

ANS.: C

81. For faithful amplification, a transistor must___ :
    1. Input forward biased
    2. Output reverse biased
    3. Work in operating point
    4. All of above

ANS.: D

82. Class A amplifier coupled with transformer what will be efficiency
    1. 50
    2. 5
    3. 75
    4. 40

ANS.: A

83. Which allow to equalize power factor of two alternator
    1. governor
    2. automatic voltage regulator
    3. syncroscope
    4. none

ANS.: B

84. When tow generators are running in parallel and field of one of them is weakened too much then it will
    1. deliver large share of the total load
    2. deliver small share of the total load
    3. run in the opposite direction
    4. run as a motor in the same direction

ANS.: D

85. Which of the following are true about a temp measuring circuit 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 temp

1. 2 only
2. 1 & 2 only
3. 1 & 3 only
4. 2 & 3 only

ANS.: C

86. The basic control action of a magnetic amplifier depends upon _____________.
    1. Variations in the load capacitance
    2. changes in inductance
    3. type of core material
    4. construction of the core

ANS.: B

87. Which of the following is true for syncronoscope
    1. One of the coil in the armature is fed through a capacitor while other is through resistance
    2. The coil produces a three phase rotating field
    3. the rotating armature has two coils windings perpendicular to each other.
    4. The field produces by the coils rotates the magnetic armature pointer at a speed relative to the frequency of the bus bar supply

ANS.: C,D

88. Which of the following is true regarding distribution system on tankers?
    1. High voltage distribution system not allowed on tankers
    2. Earthed neutral system used.
    3. 3kv above insulated neutral system used fwd of the engine room bulkhead
    4. none of the above

ANS.: C

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

1. I, II, III and IV
2. I, II and IV
3. I, II and III
4. II and IV only

ANS.: D

90. BJT transistor used as an amplifier it operates in
    1. cut off
    2. well saturation
    3. well in saturation
    4. active region

ANS.: D