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An # represents the correct answer
1. A capacitor is fully charged after 25 seconds to a battery
voltage of 20 Volts. The battery is
replaced with a short circuit. What will be the voltage across
the capacitor after one time
constant?
a) 12.64 volts
# b) 7.36 volts
c) 0 volts
2. The voltage rating of a capacitor is
# a) the max voltage that can be constantly applied
b) the min voltage required to charge
c) the normal operating voltage
3. The relative permittivity of a capacitor is
# a) the relative permittivity of the dielectric in relation to
a vacuum
b) the permittivity of dielectric in relation to dry air
c) the permittivity of the dielectric
4. Magnetic inclination is the least at the
a) poles
# b) equator
c) isoclines
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5. Ferromagnetic materials can be magnetized
a) within a band of temperatures
b) above a certain temperature
# c) below a certain temperature
6. Faradays Law States that
# a) the magnitude of the EMF is directly proportional to the
rate of change of flux
b) the magnitude of the EMF is indirectly proportional to the
rate of change of flux
c) the magnitude of the EMF is directly proportional to the
magnetic flux
7. To reduce eddy currents in a transformer you would
# a) reduce the thickness of laminations in the magnetic
core
b) increase the thickness of laminations in the magnetic
core
c) reduce the number of turns on the primary winding
8. A transformer has an input of 400V and a ratio of 2:1. If the
transformer is delta / star
wound, what will the line voltage output be?
a) 115V
b) 200V
# c) 346V
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9. What is the phase difference in a circuit with 100V, drawing
0.5 amps, consuming 50
Watts?
a) 45
b) 90
# c) 0
10. In an A.C circuit, what happens if frequency is reduced?
a) Capacitive elements may be damaged
# b) Inductive elements may be damaged
c) There will be no effect
11. A Transformer with 115v primary voltage and a ratio of 5:1
is supplying a landing light
(load 24v 45 amps) is used, what is the current drawn?
a) 205 amps
# b) 9 amps
c) 4.5 amps
12. A Transformer has 4500 secondary turns and 750 primary
turns. Its turns ratio is
a) 1:6
# b) 6:1
c) 1/6
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13. Two inductive coils are placed in close proximity with each
other at 90 degrees. The
number of flux linkages is
# a) 0
b) maximum positive
c) maximum negative
14. A high pass filter will?
# a) allow frequencies above a certain value to pass
b) allow frequencies below a certain value to pass
c) allow frequencies within a range to pass
15. If you apply this waveform to this circuit, what is the
output across the capacitor?
a) Zero
b) Pulsed negative
# c) Pulsed positive
16. What value is the same as the equivalent D.C. heating
effect?
# a) Root Mean Square
b) Average
c) Peak
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17. What is the relationship between the voltage and the current
in an A.C circuit containing
resistance & inductance?
a) Current leads voltage by up to 90
# b) Current lags voltage by up to 90
c) Current lags voltage by 90
18. What shape is the waveform when the input pulse and the time
base are unequal?
a) Square
# b) Rectangular
c) Saw tooth
19. A sine wave has 5 amps RMS value. What is the peak
value?
a) 6.37 amps
# b) 7.07 amps
c) 10 amps
20. In this circuit
# a) current leads voltage
b) current lags voltage
c) current = voltage
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21. Decreasing the field current in a shunt motor will
a) increase speed and decrease torque
# b) increase speed and increase torque
c) decrease speed and increase torque
22. Power factor relates to
# a) true power and apparent power
b) KW and KVAR
c) horsepower and Watts
23. In a delta-connected generator
# a) line volts = phase volts, line current = root 3 times phase
current.
b) line volts = phase volts, line current = phase current
divided by root 3
c) line voltage = root 3 times phase voltage, line current =
phase current
24. If current lags voltage by 90, the circuit is
a) capacitive
b) resistive
# c) inductive
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25. In a 3 phase motor, if 1 phase is lost, the motor
# a) remains at the same speed
b) runs at 1 third speed
c) runs at 2 thirds speed
26. A three-phase motor has the windings
# a) 120 apart
b) 90 apart
c) 180apart
27. When measuring the phase and line voltages of a generator,
it was found that line and
phase voltages were equal. The generator is?
# a) delta wound
b) star wound.
c) either delta or star wound
28. To change the direction of a 3-phase induction motor you
would
# a) swap two of the stator connections
b) swap all of the input connections
c) remove one of the input connections
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29. To calculate generator output you need to know the
a) armature speed and number of series conductors
b) armature speed and number of parallel conductors
# c) armature speed and field strength
30. In a shunt motor, if you reverse both field current and
armature current, the motor will
a) stop
b) change direction
# c) continue to run in the same direction
31. The permanent magnet in an A.C generator induces
# a) A.C. in the exitor generator
b) D.C. in the exitor generator
c) A.C. in the main generator
32. What does the following circuit represent?
a) Integrator
b) Low pass filter
# c) Differentiator
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33. What charge does the nucleus of an atom possess?
# a) Positive
b) Negative
c) Neutral
34. What is the maximum number of electrons in shell N of an
atom?
a) 16
# b) 32
c) 18
35. Two 10V, 20 Ah batteries are connected in parallel and
connected across a 10-ohm load.
How long could they supply normal current before the voltage
begins to decay?
a) 20 hours
b) 4 hours
# c) 40 hours
36. A 10 V battery supplies a resistive load of 10 ohms for 1
minute. What is the power
supplied
a) 100 W
b) 10 VA
# c) 10 W
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37. A 10V battery supplies a resistive load of 10 ohms for 1
minute. What is the work done?
a) 60J
b) 10J
# c) 600J
38. Three capacitors 10 microfarads, 10 nanofarads and 10
millifarads are connected in
parallel. What is the total capacitance?
# a) 10.01001mF
b) 111mF
c) 1.001001mF
39. If a 1mF capacitor has a potential difference across it of
5V what is the energy stored?
a) 12.5 J
# b) 12.5 mJ
c) 25 mJ
40. A capacitor is fully charged after 25 seconds to a battery
voltage of 20 V. The battery is
replaced with a short circuit. What will be the voltage across
the capacitor after 1 time
constant?
a) 12.64 V
# b) 7.36 V
c) 0 V
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41. Glass is an example of a
a) paramagnetic material
# b) diamagnetic material
c) coercive material
42. Which of the following is absolute permeability?
# a)
b) o
c) r
43. A solenoid of 10 turns per meter carries a current of 5A. If
the current is reduced to 2.5A,
how many turns would be required to maintain the same magnetic
field?
a) 5
b) 50
# c
44. The point of coercivity occurs when the
a) magnetizing force applied causes the material to become
magnetically saturated.
# b) magnetic flux is zero even though a magnetizing force is
being applied.
c) magnetizing force reaches a peak positive or negative
value.
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45. What is the mutual inductance if two coils of 10mH and 500mH
have 90% of the flux
transferred from one to the other?
a) 4.5mH
b) 459mH
# c) 63mH
46. An inductor has 1,000 turns of wire and a cross sectional
area of 0.001m2. If the core has
a permeability of 0.000,001 and the coil is 0.1m what is the
value of the inductor
# a) 10mH
b) 100microH
c) 100mH
47. Three inductors 10 mH, 5 mH and 20 mH are connected in
parallel. What is the total
inductance?
a) 35mH
# b) 2.86mH
c) Without knowing the coupling factor the total inductance
cannot be found
48. If the current reaches a maximum through an inductor of 2A
in 15 secs, what is the
current after 3 secs?
# a) 1.26A
b) 0.63A
c) 1A
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49. If the phase voltage in a star connected generator is 200V
what will be the line voltage?
a) 115V
b) 200V
# c) 346V
50. A generator is labeled as having 115V/200V, 20A and PF 0.8.
What is the apparent power
in each line that the generator can produce?
a) 2.3kW
b) 2.3kVA
# c) 4kVA
51. A starter generator has a
a) low resistance series field and a low resistance shunt
field
# b) low resistance series field and a high resistance shunt
field
c) high resistance series field and a low resistance shunt
field
52. Thermocouple harnesses are made from the same materials as
the thermocouple so that
a) they will not corrode
# b) mini junctions are not formed
c) the resistance is not increased beyond limits
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53. An oxygen molecule is made up of
# a) two oxygen atoms sharing electrons
b) two oxygen atoms sharing neutrons
c) two oxygen atoms sharing protons
54. A capacitor in a single phase AC motor is to
a) prevent spikes
b) block DC
# c) provide a phase shift
55. The slip speed of an induction motor is
# a) stator speed - rotor speed
b) stator speed + rotor speed
c) stator speed
rotor speed
56. The primary winding of a 3-phase transformer
a) is delta wound
b) is star wound
# c) could be either delta or star wound
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57. The symbol for flux density is
a) H
# b) B
c)
58. A galvanometer measures
a) millivolts
b) megohms
# c) milliamps
59. A battery rated at 40 Ah will supply 200 mA for
# a) 200 hours
b) 5 hours
c) 20 hours
60. The unknown resistance R in the wheatstone bridge shown
is
a) 1 ohm
# b) 4 ohms
c) 16 ohms
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61. Which of the following materials is easiest to
magnetize?
# a) Soft iron
b) High grade steel
c) Cast iron
62. AC generators are rated in
a) kVARs
b) kW
# c) kVA
63. To find which end of an electromagnet is the north pole, use
the
a) Fleming's Left Hand Rule
# b) Right Hand Clasp Rule
c) Cork Screw Rule
64. A capacitor with double the area and double the dielectric
thickness will have
a) double the capacitance
b) half the capacitance
# c) the same capacitance
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65. In a transformer, if the rate of change of current
increases, the mutual inductance will
a) increase
b) decrease
# c) remain the same
66. If the brake coil on an actuator motor goes open circuit,
the actuator will
a) over-ride its mechanical stops
# b) stop
c) run slower
67. The frequency of the output of a 4 pole generator is 400 Hz.
The generator is turning at
# a) 12000 RPM
b) 6000 RPM
c) 3000 RPM
68. What is the wave shape of the x-axis input of a traversing
oscilloscope image?
a) square
b) rectangular
# c) triangular
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69. An inductance/resistance motor is
a) better than a capacitance motor
b) restricted to low loads only
# c) less efficient than a capacitance motor
70. The voltage at point A is
# a) 7 V
b) 21 V
c) 28 V
71. A 4:1 step down transformer draws 115 V and 1 A. The output
power will be
# a) 28.5 V at 4 A
b) 28.5 V at 16 A
c) 460 V at 0.25 A
72. The voltage induced in the stator of an AC generator is
produced by
a) a fixed magnetic field
# b) a rotating magnetic field
c) an alternating field
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73. A low frequency supply
# a) may damage inductive components
b) will have no effect on inductive components
c) will make the circuit operate faster due to the reduced
impedance
74. A zinc-carbon battery life depends upon
a) the purity of the carbon rod
# b) the amount of zinc
c) the amount of the electrolyte paste
75. When checking the s.g. of the electrolyte in a lead acid
battery, you should
# a) check all cells because they may be different
b) check only the no. 1 cell because it is the master cell
c) check any cell because they will all be the same
76. If electrons are added to an atom it becomes
a) a positive ion
# b) a negative ion
c) a neutral ion
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77. An element whose atoms have fewer than 4 electrons in their
valency shell are
# a) good conductors
b) good insulators
c) semiconductors
78. In a purely resistive AC circuit, the current vector is
# a) in phase with the voltage vector
b) +90o out of phase with the voltage vector
c) -90o out of phase with the voltage vector
79. The PD at the terminals of an open circuit battery with a
small internal resistance will
be
a) more than the EMF
b) less than the EMF
# c) the same as the EMF
80. The diagram shows a 200 V long shunt generator. What is the
voltage dropped across the
series resistor?
a) 200 V
# b) 0.12 V
c) 0.2 V
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81. An electrolytic capacitor is used where
a) minimum losses are essential
# b) there is a polarized input
c) high frequency AC is used
82. If a connection to an AC motor is disconnected, the motor
will
a) slow down and stop
# b) continue to run
c) stop
83. A band stop filter
# a) stops a narrow range of frequencies
b) stops frequencies either side of a narrow range
c) attenuates frequencies either side of a narrow range
84. This is a diagram of a
a) band pass filter
b) high pass filter
# c) low pass filter
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85. When comparing the average values of an AC generator output,
to the peak values
a) average voltage = same as the peak voltage
# b) average voltage = 0.63 x peak voltage
c) average voltage = 0.707 x peak voltage
86. A parallel circuit at resonance has
# a) maximum impedance
b) minimum impedance
c) zero impedance
87. A resistor dissipates 80 Watts. If it runs for 4 hours 15
minutes, how much energy is
dissipated in total?
# a) 1.224 MJ
b) 20.4 kJ
c) 191.25 J
88. The earth lead of a 24 V equipment is 0.5 ohm resistance and
carries 80 A. How much
power does it dissipate?
# a) 3.2 kW
b) 1.152 kW
c) 1.92 kW
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89. What must you do to make a 3 F capacitor circuit into a 2 F
circuit?
a) Put a 1 F capacitor in series
b) Put a 2 F capacitor in parallel
# c) Put a 6 F capacitor in series
90. The time required to fully charge a 1 F capacitor in series
with a 100k ohm resistor is
# a) 100 ms
b) 1 s
c) 100 s
91. A 10 ohm resistor has a 14.14 V peak drop across it. What
power is dissipated?
a) 19.99 W
# b) 10 W
c) 1.414 W
92. This is a symbol for
# a) a voltage dependant resistor
b) a variable differential resistor
c) a visual display rectifier
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93. If a generator speed is halved and the field strength is
doubled, the voltage output will be
a) halved
b) doubled
# c) unchanged
94. Point A on the armature of the generator shown is
producing
# a) maximum current
b) minimum current
c) zero current
95. An accumulation of hydrogen on the plates of a battery is
known as
a) hydration
# b) polarization
c) ionization
96. What is the power dissipated in a 500 ohm resistor with a 3A
flow?
a) 1.5 kW
# b) 4.5 kW
c) 750 kW
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97. Which of the following is 1 Amp?
# a) 1000 mA
b) 1000 A
c) 1000 kA
98. A paramagnetic material has a relative permeability of
# a) greater than unity
b) less than unity
c) zero
99. What part of a battery is covered in hydrogen during
polarization?
a) Cathode
# b) Anode
c) Both the anode and the cathode
100. Electricity conducts through
a) solids only
# b) solids and liquids
c) vacuum
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101. The term that describes the combined resistive forces in an
AC circuit is
# a) impedance
b) resistance
c) total resistance
102. How can the direction of rotation of a DC electric motor be
changed
# a) reverse the electrical connections to either the field or
armature windings
b) interchange the wires which connect the motor to the external
power source
c) rotate the positive brush one commutator segment
103. An example of a good electrical insulator is
# a) glass
b) aluminium
c) mercury
104. The only practical method of maintaining a constant voltage
output from an aircraft
generator under varying conditions of speed and load is to vary
the
# a) strength of the magnetic field
b) number of conductors in the armature
c) speed at which the armature rotates
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105. An accumulation of hydrogen on the plates of a battery is
known as
a) hydration
# b) polarization
c) ionization
106. Which of the following is most likely to cause thermal
runaway in a nickel-cadmium
battery
a) excessive current draw from the battery
# b) high current charging of the battery to more than 100
percent of its capacity
c) a high internal resistance condition
107. Electric motors are often classified according to the
method of connecting the field coils
and armature. Aircraft engine starter motors are generally of
which type
a) compound
b) shunt (parallel)
# c) series
108. If a heavy mechanical load is removed from a series
motor
a) the speed will decrease and the armature current will
decrease
# b) the speed will increase and the armature current will
decrease
c) the speed will increase and the armature current will
increase
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109. Static charges remaining in an aircraft are dissipated
by
# a) the use of a conducting type nose wheel
b) bonding the aircraft to a refuel tanker
c) earthing the aircraft as soon as possible
110. Total resistance in parallel for R1 and R2 is
# a) RT = (R1 x R2) (R1 + R2)
b) RT = 1/R1 + 1/R2
c) 1/RT = 1/R1 + 1/R2
111. The quill drive on an aircraft generator
a) makes possible the use of roller
b) damps out any commutator ripple
# c) damps out vibrations
112. The method of ascertaining the voltage of a standard
aircraft lead-acid battery is by
checking
a) the voltage on open circuit
b) the voltage with rated load switched ON
# c) the voltage off load
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113. If the correct supply were connected to a DC shunt motor
which had lost its residual
magnetism it would
a) fail to run
b) run in the reverse direction
# c) run normally
114. A loss of electrical insulation results in
# a) a short circuit between the supply and earth
b) an open circuit between the supply and earth
c) an open circuit in the supply
115. A DC circuit containing a total resistance of 100 ohms has
a current flow of 250 mA. The
power dissipated in the circuit is
a) 0.4 watts
# b) 6.25 watts
c) 5 watts
116. Power is the rate of doing work. It is measured in
# a) joules/second
b) watts/second
c) joules x seconds
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117. Ohm's law states that:
a) e.m.f. = current divided by resistance
b) resistance = current divided by e.m.f.
# c) current = e.m.f. divided by resistance
118. If the resistance of a resistor which is in series with two
other resistors is doubled
a) the current in that resistance is doubled
b) the current in that resistance is halved
# c) the volts drop across that resistor increases
119. One purpose of a growler test is to determine the presence
of:
# a) a shorted armature
b) an out-of-round commutator
c) a broken field lead
120. Through which material will magnetic lines of force pass
the most readily?
a) aluminium
# b) iron
c) copper
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121. Electricity conducts through
a) solids only
# b) solids and liquids
c) vacuum
122. The secondary coil of a transformer has 1500 turns and 10
resistance. The primary coil has 1 k resistance. How many turns
does the primary coil have?
# a) 15,000
b) 150,000
c) 1,500,000
123. Two batteries 12V and 40 Ah each, are in series. What is
the total capacity?
a) 12V 80 Ah
b) 24V 80Ah
# c) 24V 40 Ah
124. In a star wound primary transformer, how could you wind the
secondary winding?
a) star only
b) delta only
# c) either delta or star
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125. The phases in supply to a 2 phase motor are
electrically
# a) 90 degrees apart from each other
b) 180 degrees apart from each other
c) 120 degrees apart from each other
126. A 30 KVA rated generator has a power factor of 0.8. What is
its maximum consistent
power
a) 30 KW
# b) 24 KW
c) 37.5 KW
127. A 50 F capacitor is fed with a current of 25 mA. How long
will it take to charge it to 100V?
a) 1 s
# b) 0.2 seconds
c) 12 minutes
128. The total resistance of the circuit shown is
a) 1.33 Ohms
b) 12 Ohms
# c) 3 Ohms
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129. A step up transformer has
a) one winding
# b) two windings
c) three windings
130. The three voltages of a three phase generator are
connected
# a) independently of each other
b) in series with each other
c) in parallel with each other
131. E.M.F. in an electric circuit corresponds to what in a
magnetic circuit
# a) mmf
b) flux
c) reluctance
132. Time constant of an inductor is
a) LR
# b) L/R
c) L2/R
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133. Permanent magnets have
a) high reluctance, low coercive force
b) low reluctance, high coercive force
# c) high reluctance, high coercive force
134. A.C. value that can produce the same heat as D.C. is
called
# a) r.m.s value
b) average value
c) peak value
135. If a battery has got low internal resistance, then
a) on load voltage will be greater than no load voltage
# b) no load voltage will be greater than on load voltage
c) no load voltage will be the same as on load voltage
136. in a parallel R, L, C circuit, the value of the capacitor
is quadrupled, then the value of the
impedance would
# a) reduce
b) increased
c) remain the same
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137. In a circuit C = 25 microfarads and the current flow is 40
microamps for 4 seconds.
What is the voltage
a) 12.8V
# b) 6.4V
c) 3.2V
138. A 3, 5 and 2 ohms resistance is connected in series with a
10 V battery. The voltage across
the 2 ohms resistor is
a) 10V
# b) 2 V
c) 4 V
139. The power in a circuit when voltage and resistance is given
can be found by
a) VxR
# b) VxV / R
c) VxVxR
140. A piezoelectric device generates electricity through
# a) pressure
b) friction
c) light
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141. Conventional current flow inside a battery is from
# a) anode to cathode
b) cathode to anode
c) either anode to cathode or cathode to anode, depending on the
active elements
142. Potentiometers are used as a
# a) variable voltage source
b) variable resistor
c) variable current source
143. In a transformer core loss is 200 W and copper loss is 220W
at no load.
What is the core loss at full load
# a) 200 W
b) 220 W
c) 0 W
144. Calculate the speed of a 400 Hz, 4 pole machine
# a) 12,000 rpm
b) 6000 rpm
c) 8000 rpm
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145. The purpose of end travel microswitch in a linear actuator
is to
# a) remain closed and opens at end travel only
b) remain open and closes at end travel only
c) remain open during normal operation and only close if the
actuator overruns its stops
146. Linear actuators used in aircraft are of
# a) split field series wound type.
b) split field shunt wound type
c) compound wound type
147. If a generator sparks, a possible reason is
# a) The brush springs are loose
b) The brushes have been placed around the magnetic coil
c) Magnetic flux deflecting the EMF
148. The charge on a proton is
a) neutral
# b) positive
c) negative
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149. in conventional current flow, what is Fleming's right hand
rule used for
a) Motors
# b) Generators
c) Inductors
150. In a capacitive circuit, if the frequency is increased
# a) the current increases
b) impedance increases
c) reactance remains the same
151. Three 12 F capacitors are in series. The total capacitance
is
a) 12 F
# b) 4 F
c) 36 F
152. A 500 ohm resistor carries a 3 amp current. What is the
power dissipated?
a) 5 kW
# b) 4.5 kW
c) 500 W
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153. A paramagnetic material has a relative permeability
a) less than unity
# b) greater than unity
c) equal to unity
154. What is the PD of a circuit which has a 40 mA current and a
1 k ohm resistance?
a) 400 V
b) 4 V
# c) 40 V
155. The time constant of a capacitor is the time
# a) for the emf to reach 36.8% of maximum
b) the current to reach 70.7% of maximum
c) to reach maximum current
156. The secondary winding of a transformer has an impedance of
10 ohms and 1500 turns.
For the primary winding to have an impedance of 1 k ohm, how
many turns must it have?
a) 15,000
# b) 150,000
c) 1,500,000
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157. A potentiometer has which of the following properties?
# a) 3 terminals
b) preset values
c) wire wound
158. A 3 ohm resistor dissipates 27 Watts. How much current
flows through it?
# a) 3 A
b) 9 A
c) 0.15 A
159. in a 2 phase generator, how far apart are the windings
electrically?
a) 45o
# b) 90o
c) 180o
160. The SI unit of work is
a) Joules per second (Watts)
# b) Kilogram metres - force
c) Joules per metre
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161. in the circuit below, what happens to the total circuit
impedance if L is tripled?
# a) Increases
b) Remains the same
c) Reduces
162. in a voltaic cell, what is the build-up on the cathode
called?
a) Polarization
# b) Sulphation
c) Hydration
163. A sine wave has a periodic time of 0.5 milliseconds. What
is the frequency
a) 200 Hz
# b) 2 kHz
c) 20 kHz
164. Three branches in a circuit have currents entering of 3A, 4
A and 5 A. A forth branch
has 10 A leaving. A fifth branch must have
a) 2A entering
# b) 2A leaving
c) 22A leaving
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165. Where are the output windings on an AC generator?
# a) Stator
b) Rotor with slip rings
c) Rotor with commutator
166. If the field strength of a generator is doubled, and the
speed is doubled, the output EMF
will
# a) quadruple
b) double
c) stay the same
167. If the rate of change of current is halved, mutual
inductance will
a) double
# b) stay the same
c) halve
168. If a capacitor of 50 microfarads has a current of 25 mA,
how long does it take to charge
to 100 V
# a) 200 milliseconds
b) 200 seconds
c) 150 seconds
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169. in a Wheatstone Bridge, the ammeter reads zero, and the
variable resistor is adjusted to
5 ohms. Resistor P has a value of 10 ohms and Q has a value of
100 ohms. What is the value
of the unknown resistor?
# a) 0.5 ohms
b) 5 ohms
c) 50 ohms
170. in a tuned circuit at resonance, the circuit will be
a) inductive
# b) resistive
c) capacitive
171. The time constant for an inductor is
# a) L/R
b) R/L
c) L x R
172. In a DC motor the pole pairs are
# a) imbedded within the field coils
b) part of the armature
c) connected to the brush gear
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173. Eddy currents in a transformer core are reduced by
# a) decreasing the thickness of the laminates
b) increasing the thickness of the laminates
c) making the core from a solid block
174. Transformer copper loss on full load is 220 Watts. On half
load the loss will be
a) 110 Watts
b) 440 Watts
# c) 55 Watts
175. The earth's magnetic field is greatest at the
# a) magnetic poles
b) geographic poles
c) magnetic equator
176. If a 1 ohm circuit produces a 50 W output, the phase angle
is
# a) 0o
b) 90o
c) 45o
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177. A series wound DC motor, the field has
# a) few turns of thick wire
b) few turns of thin wire
c) many turns of thin wire
178. What effect do the electrons of one atom have upon the
electrons of another atom?
# a) They repel each other
b) They attract each other
c) They have no effect on each other
179. What is a molecule?
# a) The smallest part of a compound
b) The smallest part of an electron
c) The smallest part of an atom
180. A coulomb is
a) one ampere per second
# b) one ampere x second
c) one second per ampere
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181. in a circuit containing three resistors of equal value
connected in parallel, one resistor
goes open circuit. The current in the other two resistors
will
a) increase
b) decrease
# c) remain the same
182. 20 amperes flow for 20 seconds. How many coulombs has
flowed?
# a) 400
b) 20
c) 1
183. An atom is
# a) the smallest part of an element that retains its
characteristics
b) the smallest part of a compound that can exist
independently
c) the smallest particle of matter
184. A neutron is a particle which is
# a) contained within the nucleus of most atoms
b) orbits the nucleus of the atom
c) contained in the nucleus of all atoms
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185. An electric current is a flow of
a) electrons from a positively charged area to a negatively
charged area
b) protons from a positively charged area to a negatively
charged area
# c) electrons from a negatively charged area to a positively
charged area
186. An element could be considered to be a conductor if it
has
a) a large number of electrons
b) a large number of electrons in its outer orbit
# c) a small number of electrons in its outer orbit
187. A volt can be considered to be a
# a) unit of electrical pressure
b) quantity of electrical energy
c) unit of electrical power
188. If the resistance of an electrical circuit is increased
a) the voltage will increase
b) the current will increase
# c) the current will decrease
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189. If 2 coulombs flowed through a circuit in 2 seconds, the
circuit would have
a) 2 volts PD
b) 2 amps
# c) 1 amp
190. In general, increasing the cross sectional area of an
electrical cable
# a) enables it to carry more current
b) enables it to carry more voltage
c) increases its resistance
191. Doubling the running time of an electrical machine
would
# a) double the joules used
b) double the watts used
c) double the current used
192. What is 3.25 volts in millivolts
a) 3.25 millivolts
# b) 3,250 millivolts
c) 325,000 millivolts
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193. Electromotive force is measured in
a) Watts
b) Ohms
# c) Volts
194. Six resistors each of 6 ohms would be
a) 36 ohms in parallel
b) 1 ohm in series
# c) 1 ohm in parallel
195. A capacitor in a single phase motor is to
# a) provide a phase shift
b) prevent sparking at the switch
c) provide smoothing
196. The mass of an atom is contained mainly in the
a) electron
# b) nucleus
c) proton
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197. The line voltage from a generator with a delta type
connection will be
a) higher than the phase voltage
b) lower than the phase voltage
# c) the same as the phase voltage
198. On a linear actuator, the field cutoff coil will be
energized when
# a) the actuator is running
b) the actuator is not running
c) only as the actuator commences movement
199. Kirchhoff's law states
# a) the algebraic sum of all the voltages entering or leaving a
series of components will be
equal to zero
b) the algebraic sum of all the currents entering or leaving a
series of components will be
equal to one
c) the inverse sum of all the voltages entering or leaving a
series of components will be
equal to one
200. The lines of magnetic flux from a magnet will
# a) repel each other
b) attract each other
c) have no effect upon each other
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201. A photozoidal cell produces electricity when subjected
to
# a) light
b) heat
c) pressure
202. A thermocouple indicator is basically a type of
a) milliammeter
# b) millivoltmeter
c) milliohmeter
203. An electric motor produces a force of 5 N at a distance of
0.2m from the centre of
rotation and rotates at a speed of 100 revs/sec. The motors
output is
a) 100 horsepower
# b) 628.4 watts
c) 314.2 watts
204. A potentiometer varies
# a) voltage
b) current
c) resistance
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205. Starter motors are usually
# a) series wound
b) compound wound
c) shunt wound
206. How can it be determined if a transformer winding has some
of its turns shorted
together?
a) measure the input voltage with an ohmmeter
# b) the transformer will get hot in normal operation
c) the output voltage will be high
207. An advantage of a star connected generator over a delta
connected generator is
a) a balance load is guaranteed
# b) two potentials are available
c) the line and phase voltages are equal
208. What does a rectifier do?
a) Changes direct current into alternating current
# b) Changes alternating current into direct current
c) Reduces voltage
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209. Two 12V 40 amp hour batteries connected in parallel will
produce
a) 24V 80 ah
# b) 12V 80 ah
c) 24V 40 ah
210. When an atom loses or gains an electron it is called
a) a current
# b) an ion
c) a molecule
211. A circuit has a resistance of 50 ohms and an inductance of
0.2 Henry. If it is connected to
a 200 volt 50 Hz supply the reactance will be
a) 31.42 ohms
# b) 62.84 ohms
c) 6.284 ohms
212. A 24-volt source is required to furnish 48 watts to a
parallel circuit consisting of four
resistors of equal value. What is the voltage drop across each
resistor?
a) 12 volts
# b) 24 volts
c) 3 volts
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213. Of the following which pair of materials would most readily
become magnetized?
a) copper and steel
b) nickel and bronze
# c) iron and steel
214. The formula for resistance in series is
# a) RT = R1 + R2 + R3...RN
b) RT = R1 x R2 x R3...RN
c) 1/RT = 1/ (R1 x R2 x R3 ...RN)
215. The core material used for an electromagnet is soft iron
because
# a) it demagnetizes easily
b) its magnetism is not easily destroyed
c) it retains most of its flux density when demagnetized
216. What is the combined value of resistances of 4 ohm and 6
ohm connected in parallel?
a) 24 ohm
# b) 2.4 ohm
c) 0.24 ohm
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217. Permanent magnets in an AC generator are
# a) to provide initial excitation
b) to control the frequency
c) to rectify the current
218. The method of ascertaining the voltage of a standard
aircraft lead-acid battery is by
checking
# a) the voltage off load
b) the voltage on open circuit
c) the voltage with rated load switched ON.
219. Generator brushes are normally made of
# a) carbon
b) brass
c) steel
220. If the voltage across a resistor is doubled
# a) the current is doubled
b) the resistance is halved
c) the current is halved
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221. As the generator load is increases (within its rated
capacity), the voltage will
a) remain constant and the amperage output will decrease
b) decrease and the amperage output will increase
# c) remain constant and the amperage output will increase
222. If a number of resistors are connected in parallel, the
total resistance is
a) the same as the lowest
# b) smaller than the lowest
c) greater than the lowest
223. A charged body is said to have
# a) a surplus or deficiency of electrons
b) a surplus of protons
c) a deficiency of neutrons
224. The ratio between apparent power and true power is the
a) efficiency
b) power rating
# c) power factor
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225. The voltage output of a generator is controlled by
a) varying the current of the output
b) varying the resistance of the output
# c) varying the current of the field
226. The total current flowing in a circuit of 200 lamps in
parallel, each of a resistance of 400
ohm and connected across an input of 100 volts is
# a) 50 amps
b) 25 amps
c) 40 amps
227. The current flowing in the armature of a DC motor is equal
to
a) (applied volts - generated volts) x armature resistance
b) applied volts + generated volts
armature resistance
# c) applied volts - generated volts
armature resistance
228. In the circuit shown the 24 volt battery has an internal
resistance of 1 ohm and the
ammeter indicates a current of 12 amperes. The value of the load
resistance is
# a) 1 ohm
b) 2 ohms
c) 6 ohms
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229. One advantage of using Ac electrical power in aircraft
is
# a) the greater ease in stepping the voltage up or down
b) AC electrical motors can be reversed while dc motors
cannot
c) the effective voltage is 1.41 times the maximum instantaneous
voltage; therefore, less
power input is required
230. The quill drive on an aircraft generator
a) makes possible the use of roller bearings at the drive
end
# b) damps out vibrations
c) damps out any commutator ripple
231. The amount of electricity a capacitor can store is directly
proportional to the
a) distance between the plates and inversely proportional to the
plate area
b) plate area and is not affected by the distance between the
plates
# c) plate area and inversely proportional to the distance
between the plates
232. When resistors are in parallel, the total resistance is
# a) smaller than the smallest resistor
b) the sum of all the resistors
c) larger than the smallest resistor
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233. What device is used to convert alternating current, which
has been induced into the
loops of the rotating armature of a DC generator into direct
current as it leaves the
generator?
# a) a commutator
b) an inverter
c) a rectifier
234. Two similar 12v batteries connected in parallel will
produce
a) 24V e.m.f. with twice the capacity of each battery
b) 24v e.m.f. with the same capacity as each battery
# c) 12V e.m.f. with twice the capacity of each battery
235. Unless otherwise specified, any values given for current or
voltage in an AC circuit are
assumed to be
a) maximum values
# b) effective values
c) instantaneous values
236. If a heavy mechanical load is removed from a series
motor
# a) the speed will increase and the armature current will
decrease
b) the speed will decrease and the armature current will
decrease
c) the speed will increase and the armature current will
increase
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237. In a vector diagram showing the magnitude and direction of
the inductance, capacitance
and resistance in an AC circuit
# a) the inductive reactance would be in opposition to the
capacitive reactance and resistance
at 90 degrees
b) the inductive and capacitance reactance would be additive
with the resistance
subtractive
c) it is impossible to show values of this kind using
vectors
238. If service No. 1 is isolated from the supply busbar shown
there will be
a) an increase in supply voltage
b) a decrease in supply voltage
# c) a decrease in total current consumption
239. An increase in operating temperature in most electrical
devices carrying current results
in
# a) an increase in resistance and a decrease in current
b) a decrease in resistance and an increase in current
c) no effect on the resistance and current
240. The voltage of a secondary cell is
a) determined by the number of plates
b) determined by the area of the plates
# c) determined by the active materials on the plates
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241. The basis for transformer operation in the use of
alternating current is mutual
a) reactance
# b) inductance
c) capacitance
242. The exciter winding in a brushless AC generator is supplied
with electrical power from
a) permanent magnets
# b) the busbar
c) a rotating generator integrally mounted on the same shaft as
the AC windings
243. If the cross-sectional area of a conductor is doubled, with
voltage constant, the current
will
a) halve
# b) double
c) remain constant
244. Eddy currents in a transformer can be reduced by
a) using a special non metallic material
b) using a single solid piece of metal
# c) laminations
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245. If two resistors of 5 and 10 ohm respectively are connected
in series and the current in
the 5 ohm resistor is 1A. what is the current in the 10 ohm
resistor?
a) 1/3 amp
b) it cannot be found without knowing the applied voltage
# c) 1 amp
246. The term used to denote the strength of a magnetic field
is
a) retentivity
b) hysterisis
# c) flux density
247. At resonant frequency the phase difference between the
voltage and current of an AC
supply feeding an inductive and capacitive network is
# a) 0 degrees
b) 180 degrees
c) 90 degrees
248. What is the ratio of turns between the primary coil winding
and the secondary coil
winding of a transformer designed to triple its input
voltage?
a) primary will have three times as many turns as its
secondary
b) primary will have twice as many turns as its secondary
# c) primary will have one-third as many turns as its
secondary
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249. A direct current of 12 milliamperes flows through a circuit
which has a resistance of 1000
ohms. The power dissipated by the circuit is
a) 12 milliwatts
b) 12 watts
# c) 144 milliwatts
250. The voltage in a series circuit
# a) is different in each component
b) is the same in each component
c) is less than it would be in a parallel circuit
251. Which aircraft circuit would be most likely to use
frequency wild 200V AC?
# a) windscreen heating
b) hydraulic pump
c) standby compass
252. Why are the iron cores of most induction coils
laminated?
# a) To reduce the effects of eddy currents
b) To increase the core permeability
c) To reduce the core reluctance
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253. A 48-volt source is required to furnish 192 watts to a
parallel circuit consisting of three
resistors of equal value. What is the value of each
resistor?
a) 12 ohm
b) 4 ohm
# c) 36 ohm
254. If voltage is 100V, resistance is 25 ohms, what is the
current?
a) 2500 amperes
# b) 4 amperes
c) 0.4 amperes
255. A soft iron core is used in an ELECTRO magnet because
a) it has HIGH permeability and HIGH coercivity
# b) it has HIGH permeability and LOW coercivity
c) it has LOW permeability and HIGH coercivity
256. The resistance to electrical flow in a wire depends on
# a) the diameter, length, material of wire and temperature
b) the material only - copper or aluminum
c) the length and material of the wire only
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257. A transformer should always have its
# a) secondary open circuit or on load
b) secondary shorted or on load
c) primary shorted or off load
258. How can the direction of rotation of a DC electric motor be
changed?
a) interchange the wires which connect the motor to the external
power source
# b) reverse the electrical connections to either the field or
armature windings
c) rotate the positive brush one commutator segment
259. An AC generator's frequency will
a) always be constant regardless of the generators drive
speed
b) vary with changes in field strength
# c) be proportional to the RPM at which it is driven
260. A short circuit between the supply and earth
a) does not matter if the circuit uses the aircraft earth as a
return
# b) could be very dangerous as the current drawn will be very
high
c) is not dangerous as the current drawn will be low
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261. When two coils are linked by a common flux, a voltage can
be induced in one by a
changing current in the other. This process is known as
# a) mutual induction
b) the magnetic effect
c) self induction
262. A circuit consists of 3 ohm, 5 ohm and 12 ohm resistors in
series, the current flowing in
the 5 ohm resistor is 10 amps. What is the applied voltage?
a) 100v
b) 10v
# c) 200v
263. Copper is an inferior conductor to aluminum when
comparing
# a) weight for weight
b) load for load
c) CSA with CSA
264. In an AC circuit how is the value of true power
calculated?
# a) By volts multiplied by amps multiplied by power factor
b) By wattmeter readings multiplied by power factor
c) By voltmeter readings multiplied by ammeter readings
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265. A frequency wild AC generator is used for
a) instruments and navigation
# b) de-icing loads
c) any AC load
266. Which of the following is not one of the purposes of
interpoles in a generator?
# a) Reduce field strength
b) Overcome armature reaction
c) Reduce arcing at the brushes
267. Which of the following would be used to calculate
transformer turns ratio?
a) primary turns secondary turns
b) primary turns secondary turns
# c) secondary turns primary turns
268. A good electrical insulator is a material which
a) has more protons than electrons
# b) has its electrons tightly bound to their parent atoms
c) contains a large number of positive ions
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269. To reverse the direction of a series motor
a) the direction of the current through the field is
reversed
# b) a second series field is fitted
c) the direction of the current through the field and the
armature is reversed
270. How many cycles of AC voltage are produced in a six-pole
alternator of the revolving-
field type, with each revolution of the rotor?
a) Four
b) Six
# c) Three
271. The variable frequency output from an AC generator is used
for
# a) supplying non-inductive loads
b) the AC supply instead of using inverters
c) driving AC operated instruments
272. The capacitance of a capacitor is dependant upon
# a) the type of material separating the plates
b) the rate of change of current in the circuit
c) the charge on it
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273. A piece of equipment is rated at 750 watts and the applied
voltage is 30 volts. The value
of the protection fuse should be
a) 20 amps
# b) 30 amps
c) 15 amps
274. The current consumed by a DC starter motor will
a) remain relatively constant over the starting speed range
b) increase as the engine speed increases
# c) decrease as the engine speed increases
275. When different rated capacitors are connected in parallel
in a circuit, the total
capacitance is
a) equal to the capacitance of the highest rated capacitor
b) less than the capacitance of the lowest rated capacitor
# c) equal to the sum of all the capacitances
276. The voltage in a transformer secondary coil that contains
twice as many loops as the
primary coil will be
a) less and the amperage greater than in the primary coil
b) greater and the amperage greater than in the primary coil
# c) greater and the amperage less than in the primary coil
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277. How are generators rated?
a) Impedance at rated voltage
b) Amperes at rated voltage
# c) Watts at rated voltage
278. in a single phase AC generator, frequency is determined
by
# a) the generator speed
b) controlling the current flow through the voltage field
windings
c) the number of pairs of poles
279. The risk of a fire due to static electricity is
overcome
a) by fitting static wicks and insulating all metal
components
# b) by connecting all metal components by bonding
c) by fitting static wicks and isolating the battery from
inflammable gas sources
280. Due to armature reaction in a DC motor
# a) the trailing pole tips are magnetically weakened
b) the leading pole tips are magnetically weakened
c) the magnetic flux is restored by moving the MNA towards the
GNA
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281. Two resistors are connected in series and have an e.m.f. of
V volts across them. If the
voltages across the resistances are V1 and V2 then by
Kirchhoff's law
# a) V = V1 + V2
b) V2 = V1 + V
c) V1 = V2 + V
282. When an electrical supply becomes open-circuit
# a) the loss of continuity will prevent its component from
functioning
b) the fuse or circuit breaker should isolate the circuit due to
the increased current drawn
c) the component will operate normally but will not switch
off
283. Some electric motors have two sets of field winding wound
in opposite directions so that
the
a) speed of the motor can be more closely controlled
# b) motor can be operated in either direction
c) power output of the motor can be more closely controlled
284. The amount of electrical power for a given generator weight
is
a) determined by the size of the aircraft
b) greater for DC generator
# c) greater for AC generator
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285. When resistors are in parallel the total current is equal
to
a) the current through one resistor
# b) the sum of the currents
c) the reciprocal of all the currents
286. What is the ampere-hour rating of a storage battery that is
designed to deliver 45
amperes for 2.5 hours?
a) 90.0 ampere-hour
# b) 112.5 ampere-hour
c) 45.0 ampere-hour
287. How much power must a 24-volt generator furnish to a system
which contains the
following series loads?
5 ohm, 3 ohm and 12 ohm
a) 450 watts
b) 402 watts
# c) 28.8 watts
288. A volt meter is connected
a) in series or parallel
# b) in parallel
c) in series
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289. What polarity do interpoles take in a DC motor?
# a) The same as the next main pole behind in the direction of
rotation
b) Either, provided they lay on the MNA
c) The same as the next main pole ahead in the direction of
rotation
290. On a typical AC generator the output is taken
a) direct from the rotor via slip rings
b) direct from the exciter
# c) direct from the stator windings
291. Since electrical supplies taken from a bus-bar are in
parallel, isolating some of the
services would
# a) reduce the current consumption from the bus-bar
b) increase the current consumption from the bus-bar
c) not affect the current consumption, it would reduce the
voltage
292. One Picofarad is
a) 1 x 1012 farad
b) 1 x 10-6 farad
# c) 1 x 10-12 farad
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293. Which of these will cause the resistance of a conductor to
decrease?
a) Decrease the length or the cross-sectional area
# b) Decrease the length or increase the cross-sectional
area
c) Increase the length or decrease the cross-sectional area
294. The purpose of bonding is to
a) give generated static an easy return path to the
generator
# b) stop different potentials developing with subsequent fire
risks
c) ensure all components have been securely fitted
295. The S.I. unit of magnetic flux density is the
a) Weber
b) Henry
# c) Tesla
296. What is the principal advantage of the series-wound dc
motor?
a) Low starting torque
b) Suitable for constant speed use
# c) High starting torque
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297. Interpole windings fitted to DC series wound generators
are
a) in series with the field
b) in parallel with the armature
# c) in series with the armature
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298. One of the chief advantages of alternating current is that
it can be transmitted at a high
voltage with a low power loss; the voltage can then be changed
to any desired value of
# a) AC by means of transformers
b) DC by means of transformers
c) DC by means of inverters
299. An AC generator is producing the required voltage but a
higher frequency than that
required. To remedy this, the following action must be
taken?
a) Decrease the speed of the prime mover, and then decrease the
strength of the field
b) Decrease the speed of the prime mover
# c) Decrease the speed of the prime mover, and then increase
the strength of the field
300. How many amperes will a 28-volt generator be required to
supply to a circuit containing
five lamps in parallel, three of which have a resistance of 6
ohms each and two of which have
a resistance of 5 ohms each?
# a) 25.23 amperes
b) 1 ampere
c) 1.11 amperes
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301. The area of a hysteresis loop is proportional to the
# a) energy dissipated in putting the material through a
complete cycle of magnetization and
demagnetization
b) relative permeability of the material being magnetized
c) energy absorbed in completely demagnetizing the material
302. The current flowing through a circuit can be increased to
four times its original value by
# a) doubling the applied voltage and halving the resistance
b) halving the applied voltage and halving the resistance
c) doubling the resistance and doubling the applied voltage
303. When more than two inductors of different inductances are
connected in parallel in a
circuit, the total inductance is
a) equal to the sum of the individual inductances
# b) less than the inductance of the lowest rated inductor
c) equal to the inductance of the highest rated inductor
304. What polarity do interpoles take in a DC generator?
# a) the same as the next main pole ahead in the direction of
rotation
b) the same as the next main pole behind in the direction of
rotation
c) either, providing they lay on M.N.A.
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305. What happens to the resistance of a copper conductor when
the temperature increases?
# a) It increases
b) It decreases
c) It remains the same
306. The method most often used in overcoming the effect of
armature reaction is through the
use of
a) shaded poles
# b) interpoles
c) drum-wound armatures in combination with a negatively
connected series field
307. The core material used for an electromagnet is soft iron
because
# a) it demagnetizes easily
b) it retains most of its flux density when demagnetized
c)its magnetism is not easily destroyed
308. The switch on a DC circuit containing a fully charged
capacitor is opened. The voltage
across the capacitor
a) drops immediately to zero
b) starts to fall exponentially to zero
# c) remains equal to the original charging voltage supply
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309. in a 3 phase generator with balanced load, the potential
between the neutral point and
earth is
a) equal to line volts
b) equal to phase volts
# c) zero volts
310. A direct current of 12 milliamperes flows through a circuit
which has a resistance of 1000
ohms. The power dissipated by the circuit is
a) 12 milliwatts
b) 12 watts
# c) 144 milliwatts
311. An increase in which of the following factors will cause an
increase in the inductive
reactance of a circuit?
a) Resistance and capacitive reactance
b) Resistance and voltage
# c) Inductance and frequency
312. in transformer operation, hysteresis losses are
a) current overcoming coil resistance
b) induced current in the iron core
# c) energy wasted in reversing core magnetization
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313. The starting current of a series-wound DC motor, in passing
through both the field and
armature windings produces a
a) low starting torque
b) speed slightly higher when unloaded
# c) high starting torque
314. A non-magnetic metal
# a) has no permeability
b) has high retentivity
c) is a poor conductor
315. The power output of an AC parallel generator system is
measured in
# a) KVA
b) KW / KVARS
c) amperes
316. The shape of the output waveform of an AC generator is
known as a
# a) sine wave
b) cosine wave
c) frequency wave
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317. in a circuit containing three resistors of equal value
connected in series and one of the
resistors short circuits, the effect is for the current in the
other two resistors to
# a) increase
b) remain the same
c) decrease
318. To increase the speed of a shunt motor a resistance is
placed
a) in series with the armature
b) in parallel with the field
# c) in series with the field
319. Frequency (Hz) is the number of cycles per
a) revolution
b) minute
# c) second
320. In a series resistive circuit
a) the total voltage equals the difference between the
individual voltages
# b) the total voltage is equal to the sum of the individual
voltages
c) the total voltage is the same as the highest individual
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321. The current in a DC circuit containing a fully charged
capacitor is
# a) zero
b) is dependent upon the size of the capacitance of the
capacitor
c) maximum