Module 3

Module Three 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 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 Page 1 – Mod 3

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 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?

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a) Zero b) Pulsed negative c) Pulsed positive Page 2 – Mod 3

16. What value is the same as the equivalent D.C. heating effect? # a) Root Mean Square b) Average c) Peak 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 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

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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 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) 180°apart 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 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 Page 4 – Mod 3

32. What does the following circuit represent?

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a) Integrator b) Low pass filter c) Differentiator

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 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

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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 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) µ b) µo c) µr 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) 20 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. 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 Page 6 – Mod 3

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 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 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

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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 57. The symbol for flux density is a) H # b) B c) ø 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

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a) 1 ohm b) 4 ohms c) 16 ohms

61. Which of the following materials is easiest to magnetize? # a) Soft iron b) High grade steel c) Cast iron Page 8 – Mod 3

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 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 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

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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 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?

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a) 200 V b) 0.12 V c) 0.2 V

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

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84. This is a diagram of a

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a) band pass filter b) high pass filter c) low pass filter

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 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 µF capacitor in series with a 100k ohm resistor is # a) 100 ms b) 1 s c) 100 s Page 12 – Mod 3

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

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a) a voltage dependant resistor b) a variable differential resistor c) a visual display rectifier

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

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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 97. Which of the following is 1 Amp? # a) 1000 mA b) 1000 μA c) 1000 kA Page 13 – Mod 3

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 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 105. An accumulation of hydrogen on the plates of a battery is known as a) hydration # b) polarization c) ionization

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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 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 leadacid battery is by checking a) the voltage on open circuit # b) the voltage with rated load switched ON c) the voltage off load 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

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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 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 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 Ω resistance. The primary coil has 1 k Ω resistance. How many turns does the primary coil have? # a) 15,000 b) 150,000 c) 1,500,000 Page 16 – Mod 3

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 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 μF 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 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 Page 17 – Mod 3

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 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 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 Page 18 – Mod 3

140. A piezoelectric device generates electricity through # a) pressure b) friction c) light 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 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 Page 19 – Mod 3

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 µF capacitors are in series. The total capacitance is a) 12 µF # b) 4 µF c) 36 µF 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 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) 1,500,000 157. A potentiometer has which of the following properties? # a) 3 terminals b) preset values c) wire wound Page 20 – Mod 3

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 161. in the circuit below, what happens to the total circuit impedance if L is tripled?

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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 Page 21 – Mod 3

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 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 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 Page 22 – Mod 3

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 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 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 Page 23 – Mod 3

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 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 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 Page 24 – Mod 3

192. What is 3.25 volts in millivolts a) 3.25 millivolts # b) 3,250 millivolts c) 325,000 millivolts 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 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 Page 25 – Mod 3

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 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 209. Two 12V 40 amp hour batteries connected in parallel will produce a) 24V 80 ah # b) 12V 80 ah c) 24V 40 ah Page 26 – Mod 3

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 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 217. Permanent magnets in an AC generator are # a) to provide initial excitation b) to control the frequency c) to rectify the current

Page 27 – Mod 3

218. The method of ascertaining the voltage of a standard aircraft leadacid 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 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 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 Page 28 – Mod 3

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

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

Page 29 – Mod 3

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 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 Page 30 – Mod 3

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 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 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 Page 31 – Mod 3

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 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 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

Page 32 – Mod 3

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 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 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

Page 33 – Mod 3

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 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 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 Page 34 – Mod 3

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 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

Page 35 – Mod 3

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 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

Page 36 – Mod 3

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 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 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 Page 37 – Mod 3

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 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. Page 38 – Mod 3

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 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 Page 39 – Mod 3

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 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 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 Page 40 – Mod 3

322. The sum of the instantaneous E.M.F.'s in a three phase system is a) equal to the line voltage b) three times the phase voltage # c) zero 323. A capacitor is a barrier to a) both b) A.C # c) D.C 324. One revolution of a three phase generator will produce a) 3 cycles b) 2 cycles # c) 1 cycle 325. If the North pole of a magnet is brought nearer to the North pole of another magnet a) attraction between them will be increased # b) repulsion between them will be increased c) repulsion between them will be reduced 326. A 200 volt motor is taking 10 amperes armature current, the armature resistance is 0.1 ohm. The B.EMF under these conditions will be a) 201 volts # b) 199 volts c) 1 volt 327. What is the effect of inserting an iron core into a current carrying coil? # a) The flux density of the original magnetic field produced by the coil is increased b) The flux density of the original magnetic field remains constant c) The core tends to move from a stronger to a weaker part of the field 328. What is the total capacitance of a parallel circuit containing three capacitors with capacitance of 0.25microfarad, 0.03microfarad, and 0.12microfarad, respectively? a) 0.04 µF b) 0.04 pF # c) 0.4 µF 329. 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 Page 41 – Mod 3

330. The frequency of a power wave in an AC resistance circuit is a) the same as the frequency for voltage and current b) half the frequency for voltage and current # c) twice the frequency for voltage and current 331. The reading on the ammeter in the circuit shown is

#

a) 3A b) 6A c) 12A

332. The 'A' phase of a three phase power system is colour coded a) blue b) yellow # c) red 333. The total resistance of the circuit shown is

a) 12 Ohms # b) 3 Ohms c) 7.5 Ohms 334. What is a method used for restoring generator field residual magnetism? # a) Flash the fields b) Reseat the brushes c) Energize the armature 335. A 1µF capacitor is equivalent to # a) 0.000,001 Farads b) 1,000,000 Farads c) 0.001 Farads 336. The opposition offered by a coil to the flow of alternating current is called (disregard resistance) a) impedance b) reluctance # c) inductive reactance Page 42 – Mod 3

337. A high surge of current is required when a DC electric motor is first started. As the speed of the motor increase a) the applied emf increases proportionally b) the counter emf decreases proportionally # c) the counter emf builds up and opposes the applied emf, thus reducing the current flow through the armature 338. The tolerance of the AC generator frequency is a) 40 Hz # b) 10 Hz c) 20 Hz 339. The various parts of an aircraft airframe are maintained at the same potential by a) the supply bus-bars b) static discharge wicks # c) bonding 340. When two capacitors are connected in series a) the charge stored on each is directly proportional to its capacitance # b) the charge stored on each is the same c) the charge stored on each is inversely proportional to the voltage across it 341. Aircraft generators are cooled by a) oil cooling radiators around the main body b) fuel cooling radiators # c) ram air 342. The voltage of an AC generator a) rises to max in one direction, falls to zero and rises in the same direction # b) rises to max in one direction then falls to zero then rises to max in the opposite direction c) rises to max in one direction and remains 343. The charge on a capacitor is expressed as a) the ratio Q/V b) the product Q x V # c) the product C x V 344. A shunt is used with # a) an ammeter b) an ohmmeter c) a voltmeter Page 43 – Mod 3

345. The resistance of the current return path through the aircraft is always considered negligible, provided the a) generator is properly grounded b) voltage drop across the circuit is checked # c) structure is adequately bonded 346. An ammeter is connected into a circuit in a) parallel b) shunt # c) series 347. When handling a high voltage capacitor in an electrical circuit, be sure it a) has a full charge before removing it from the circuit # b) is fully discharged before removing it from the circuit c) has at least a residual charge before removing it from the circuit 348. When a circuit with a series inductance and capacitance is at resonant frequency a) the current in the circuit decreases # b) the impedance of the circuit is such that the voltage is in phase with the current c) the impedance of the circuit is such that the voltage leads the current by exactly 90 degrees 349. in an AC circuit, the effective voltage is a) equal to the maximum instantaneous voltage b) greater than the maximum instantaneous voltage # c) less than the maximum instantaneous voltage 350. On a combined DC starter - generator system # a) the voltage regulator is connected to the shunt field after the start cycle is completed b) the series coil is open circuit during the engine start sequence c) the voltage regulator controls the start sequence during engine starting 351. A pure capacitor, inductor and resistor are connected in series and the voltage drops across each are 10V and the total current flowing in the circuit is 1A. How much true power is the circuit consuming? a) 30VA b) 30W # c) 10W 352. If a capacitor 1µF and an inductor 10mH are connected in parallel what is their approximate resonant frequency? a) 62Hz b) 3.2MHz # c) 1.6kHz Page 44 – Mod 3

353. Which wave form is stepped positive and negative with unequal length sides? # a) Trapezoidal wave b) Rectangular wave c) Saw tooth wave 354. The value of an AC sine wave that will give an equivalent heating effect in a DC resistor is the a) average value # b) RMS value c) peak value 355. Where is the magnetic dip least? a) Poles # b) Equator c) Isoclinals 356. The dielectric constant of a capacitor is a measurement of # a) the electrostatic energy storing capacity of the capacitor dielectric b) the electrical resistance of the capacitor dielectric c) the electrical repulsion of electrons within the dielectric material 357. To reverse the direction of rotation on a DC shunt motor, you must change the direction of the current through # a) the field windings or the armature windings b) the armature windings only c) the field windings and the armature windings 358. If the field current to a shunt wound DC motor is decreased when operating at a constant load, the motor speed will a) reduce # b) increase c) not change 359. An electric current is a) a surplus of free electron b) an excitement of electrons in a metal # c) an ordered flow of electrons 360. An atom contains a) molecules b) hydrogen # c) electrons 361. What causes a transformer to be noisy? a) High coil resistance # b) An air gap in the core c) High core losses Page 45 – Mod 3

362. Carbon has a # a) negative temperature coefficient b) positive temperature coefficient c) temperature coefficient of zero 363. The peak factor for a sine wave is a) 0.707 # b) 1.414 c) 1.11 364. If a motor is spinning at 50 cycles per second, how long is 1 cycle? # a) 0.02 seconds b) 50 seconds c) 0.83 seconds 365. An integrated step input at unequal time base produces a) a square wave b) a sine wave # c) a saw tooth wave 366. A capacitor in series and inductor in parallel make what kind of filter? a) Band pass # b) High pass c) Low pass 367. If a load in series has a current passing through it, the magnetic field can be worked out by using # a) the corkscrew rule b) left hand rule c) right hand rule 368. If the current flowing into a junction is 5A, 3A, 4A in and 10A out. What is the 5th wire carrying? a) 2A in # b) 2A out c) 5A out 369. If an insulated conductor is placed near to a negatively charged rod, the nearest end of the conductor becomes a) negatively charged # b) positively charged c) No change will occur

Page 46 – Mod 3

370. If 2 resistors, one red, yellow, black, gold and the other violet, blue, black, silver were replaced by a single resistor. Ignoring tolerance, what would the color coding be? # a) Brown, black, brown b) Brown, black, black c) Black, brown, black 371. Germanium and silicon have how many electrons in their outer shell # a) 4 b) 2 c) 6 372. If a free electron is given to another atom, that atom is a a) positive ion # b) negative ion c) valency atom 373. If a nicad battery is not to be used immediately it should be stored a) fully charged # b) fully dissipated c) dry 374. A light / heat sensitive cell is a # a) transducer b) diode c) transistor 375. In a mercury cell the steel casing is # a) the positive terminal b) the negative terminal c) neither 376. To improve the life of a dry cell you would # a) use more zinc b) use more electrolyte paste c) us a a pure carbon positive rod

Page 47 – Mod 3

377. What is the voltage at A?

#

a) 26V b) 28V c) 2V

378. The unit for power is equal to a) N/m # b) Joules per second c) Volts/Amps 379. The source voltage in the circuit below is

#

a) 50V b) 200V c) 150V

380. The 5th colored band on a resistor represents the a) tolerance b) multiplier # c) reliability or temperature coefficient 381. Three 12 microfarad capacitors in parallel. The overall circuit capacitance is a) 4 microfarads b) 1 microfarads # c) 36 microfarads Page 48 – Mod 3

382. Flux density will a) increase linearly with coercive force # b) increase linearly with magnetic flux c) decrease linearly with magnetic flux 383. A transformer with a 5:1 ratio has a 24V output. What is the input a) 120 V DC b) 4.8 V AC # c) 120 V AC 384. The mark-to-space ratio of the following waveform is

#

a) A to B B to C b) A to D D to E c) D to E D to C

385. A generator supplies 25 A, 4 V and 50 W. What is the apparent power and the power factor? a) 100 VA and 2 b) 400 VA and 0.5 # c) 100 VA and 0.5 386. In a power circuit, the purpose of an inductor is # a) to dampen power surges b) to dampen current surges c) to dampen voltage surges 387. When a number of ferrite pieces are grouped together, they a) are semi-permanent magnets when DC is passed through them # b) can be used to store binary code c) electromagnets 388. Ampere turns is calculated by the number of turns # a) multiplied by current b) divided by current c) multiplied by magnetic flux Page 49 – Mod 3

389. A conventional aircraft generator will be a) series wound b) delta wound # c) star wound 390. Storage of magnets should be a) in pairs end to end b) in a non magnetic pox # c) in pairs with keeper plates 391. A circuit has 1 megohm and 8 microfarads. What is the time constant? a) 1 second # b) 8 seconds c) 40 seconds 392. Current in an inductive circuit will a) lead voltage # b) lag voltage c) be at unity 393. Power factor of a generator is a) sin ø # b) cos ø c) tan ø 394. In a an AC motor, the rotation of the MNA a) is the same as the rotation of the armature # b) is opposite to the rotation of the armature c) is slightly less speed than the rotation of the armature 395. in a wave wound generator with 4 poles, what would be the minimum number of brushes? a) 4 # b) 2 c) 8 396. A capacitor rating is # a) the maximum continuous voltage it can take b) the voltage it will rupture at c) the voltage it will charge to 397. in conventional flow, the left hand rule applies to a) generators # b) motors c) batteries

Page 50 – Mod 3

398. Copper losses in a transformer are caused by a) circulating currents through the transformer # b) the resistance in the windings c) wasting of the copper wires due to friction 399. in AC generators, 0.637 is a) RMS # b) average value c) form factor 400. In a 3 phase generator, what angle are the phases to each other? a) 180o # b) 120o c) 0o 401. In a 2 phase generator, what angle are the phases to each other? # a) 90o b) 180o c) 0o 402. Delta wound line current is a) equal to phase current # b) root 3 x phase current c) less than the phase current 403. The multiplier color coding on a capacitor is in a) farads b) microfarads # c) picofarads 404. Form Factor for a sine wave AC output is a) 0.707 b) 1.414 # c) 1.1 405. In a simple voltaic cell the collection of ions on the cathode causes a) hydration b) sulphation # c) polarisation 406. The electrolyte in a nicad battery would rise if the battery was a) discharging # b) charging c) remaining at constant voltage

Page 51 – Mod 3

407. When a conductor is cut by magnetic lines of force an EMF is induced. This is a) Lenz's Law # b) Faraday's Law c) Kerchoof's Law 408. Two 2 volt 10AH cells are connected in series, the output voltage and the capacity would be a) 2 volt, 20 AH # b) 4 volt 10 AH c) 4 volt 20 AH 409. The electrolyte in a nicad battery is a) cadmium hydroxide b) nickel hydroxide # c) potassium hydroxide 410. Referring to the drawing below, if the volts dropped across the 20 ohm resistor is 10 volts, the resistance of R1 is

# a) 20 ohms b) 16 ohms c) 2 ohms 411. The atomic number of an atom is determined by the number of # a) protons b) electrons c) neutrons 412. In a Leclanche cell the plates are made of a) mercury and lithium b) nickel and cadmium # c) zinc and carbon

Page 52 – Mod 3

413. in a simple voltaic cell, polarization reduces output voltage because of the a) transfer of material between the anode and the cathode # b) build up of hydrogen on the anode c) build up of hydrogen on the cathode 414. When the temperature of the electrolyte in a battery increases, the SG a) goes up # b) goes down c) remains the same 41 5. A 47 kilohm resistor has the following color code # a) Yellow, Violet, Orange b) Orange, Violet, Red c) Red, Orange, Yellow 416. If the temperature of a pure metal is reduced to absolute zero, its resistance will be a) infinity # b) practically zero c) unaffected 417. The bridge circuit shown will be balanced when the value of the unknown resistor R is

a) 18 ohms b) 14 ohms # c) 2 ohms

Page 53 – Mod 3

418. The current in the circuit below is

a) 5 A b) 0.2 A # c) 5 mA 419. In the previous question, the power developed across the 10 k ohm resistor is # a) 250 mW b) 250 W c) 50 mW 420. What is represented by this diagram?

# a) Potentiometer b) Rheostat c) Thermister 421. In the following circuit, the input at P is 4 amps and at Q is 5 amps. What is the voltage across the 6 ohm resistor?

# a) 54V b) 1.5V c) 6V

Page 54 – Mod 3

422. The unknown current in the network below is

a) 22A # b) 3A c) 47A 423. The Watt can be expressed as # a) Joules per second b) Joules x seconds c) Seconds per Joule 424. A single phase circuit has an input voltage of 100V. The current is 10A and the circuit has a power factor of 0.5. The true power is a) 1000W b) 50W # c) 500W 425. Power in a DC circuit is found by a) multiplying current by resistance b) multiplying the voltage by itself and dividing by the current # c) multiplying the resistance by the current squared 426. The total capacitance of the circuit shown is

# a) 4µF b) 36µF c) 3µF 427. When a capacitor is charged from a DC supply, the voltage / time curve is a) logarithmic # b) exponential c) linear Page 55 – Mod 3

428. An electrolytic capacitor is used because it has a a) large physical size for a large capacity # b) small physical size for a large capacity c) small physical size for low leakage current 429. An electrolytic capacitor would be used in circuits supplying a) heavy loads b) light loads # c) heavy / light loads 430. The symbol for flux density is a) H # b) B c) MMF 431. The hysteresis loop for a magnetic material is on a graph with a) total flux against flux density b) current against flux density # c) flux density against magnetising force 432. To determine the direction of the magnetic field around a conductor you would use # a) the corkscrew rule b) Fleming's left hand rule c) Fleming's right hand rule 433. A material with a narrow hysteresis loop a) will have high retentivity # b) will have low retentivity c) cannot be magnetised 434. If a bar magnet is cut in half a) the magnet is destroyed # b) two bar magnets are formed c) one bar magnet and one non-magnet is formed 435. The diagram shows a current carrying conductor in a magnetic field. The conductor will move

#

a) upwards b) downwards c) sideways Page 56 – Mod 3

436. The electromagnetic force between two charged bodies is a) proportional to the distance between them b) inversely proportional to the distance between them # c) inversely proportional to the square of the distance between them 437. Copper is a a) paramagnetic materials b) ferromagnetic material # c) diamagnetic material 438. Switching on or off the current in one coil produces an emf in another coil adjacent to it. The two coils are said to have a) self inductance # b) mutual inductance c) auto inductance 439. the time constant in an inductive circuit is the time required for the current to reach # a) 63.2% of maximum value b) 63.7% of maximum value c) 70.7% of maximum value 440. Self induced emf in a coil supplied with a current varying at a uniform rate can be found by a) - N dI dt b) - L dØ dt # c) - L dI dt 441. The MMF of a coil fed with 2 amps and having 10 turns is a) 5 ampere turns # b) 20 ampere turns c) 20 amperes / turn 442. An AC inductive circuit has an inductance 0f 10 mH and a frequency input of 1000Hz. The opposition to current flow is approximately a) 63,000 ohms b) 630 ohms # c) 63 ohms 443. A sine wave of RMS value 7.07 volts has a peak to peak value of # a) 10.0 volts b) 0.707 volts c) 20.0 volts Page 57 – Mod 3 444. The true power in an AC circuit is given by

#

a) voltmeter reading x PF b) volts x amps c) volts x amps x PF

445. The average value of 100 volts peak AC is a) 70.7 volts b) 141.4 volts # c) 63.7 volts 446. The RMS value of 200 volts peak to peak is # a) 141.4 volts b) 70.7 volts c) 127.4 volts 447. The impedance of a series tuned circuit at resonance is a) zero b) maximum # c) minimum 448. The copper loss on a single phase transformer is 25 Watts on full load. What will it be on half load? a) 5 Watts b) 12.5 Watts # c) 6.25 Watts 449. Rotating coil B through 90o will

#

a) increase the EMF induced into B b) decrease the EMF induced into B c) increase the EMF induced into A

450. A transformer is designed to operate at 60 Hz. It is connected across a 50 Hz supply. The primary windings would # a) draw more current b) draw less current c) draw the same current 451. A current transformer, when disconnected from a circuit must be a) left open circuit # b) short circuited c) have a resistor connected across the terminals Page 58 – Mod 3 452. What is the reflected impedance in the primary?

#

a) 20 ohms b) 500 ohms c) 50 ohms

453. A transformer rated at a frequency of 200 Hz a) may be used at any other frequency # b) may only be used at the rated frequency or above c) may only be used at the rated frequency or below 454. The dots are called, and indicate

a) quadrature dots, points are 90o out of phase # b) phasing dots, point that have the same polarity at the same moment in time c) phasing dots, point that have the opposite polarity at the same moment in time 455. The power factor of an AC circuit is the a) sine of the phase angle # b) cosine of the phase angle c) tangent of the phase angle 456. The Form Factor of an AC waveform can be found by # a) RMS value divided by the average value b) average value divided by the RMS value c) average value times the RMS value 457. A differentiator has a time constant which is a) long # b) short c) equal to the input pulse Page 59 – Mod 3 458. If the frequency is increased in an AC circuit of pure resistance, the effect is

#

a) increased resistance b) decreased resistance c) nothing

459. A wire is rotated through a magnetic field. To give DC it must be connected to # a) a commutator b) slip rings c) a rectifier 460. In an inductive resistive circuit, 1 amp flows from a supply of 100V dissipating 50 Watts of power. The phase angle is # a) 60o b) 90o c) 45o 461. A transformer is built with a material having a # a) narrow hysteresis loop b) wide hysteresis loop c) high coercive force 462. An alternator delivers 500V RMS at 1 ampere. The power factor is 0.8. The true power is a) 100VA # b) 400W c) 500W 463. in a circuit which possesses mutual inductance, current is increased to the primary # a) the induced EMF in the secondary produces a current in the secondary circuit which opposes the increase in flux due to the increase of current in the primary b) the induced EMF in the secondary produces a current in the secondary circuit which assists the increase in flux due to the increase of current in the primary c) the induced EMF in the secondary produces a current in the secondary circuit whose flux has no effect on the flux in the primary 464. A component that produces an output voltage due to incident light is called a a) liquid crystal b) light emitting diode # c) solar cell

Page 60 – Mod 3 465. If the supply to a DC shunt motor was reversed a) it would rotate in the opposite direction

#

b) it would fail to run c) it would rotate in the same direction

466. Slip on a synchronous motor on start is a) 0% b) 50% # c) 100% 467. A shaded pole motor has shaded poles to a) increase efficiency # b) create a rotating field c) reduce interference 468. A series motor draws a high current on start, and then the current reduces. This is due to a) the resistance of the field and the armature in series # b) the back EMF c) the resistance of the field and armature in parallel 469. on a brushless AC generator, the main rotating field is fed with a) AC # b) DC via diodes on the rotor c) AC from the rotating field exciter 470. Single phase components in a three phase system may be connected between a) phase A and B only b) phase and neutral only # c) any phase and neutral OR between any two phases 471. Interpoles in a DC generator are connected a) in parallel with the armature # b) in series with the armature c) in series with the field 472. in a DC generator, the effect of armature reaction may be reduced by moving the brush gear a) from MNA to GNA # b) in the direction of armature rotation towards the MNA c) against the direction of armature rotation towards the MNA 473. The windings embedded in the pole faces of a DC generator are a) interpoles b) commutating coils # c) compensating windings Page 61 – Mod 3 474. A 6 pole wave-wound generator has # a) 2 brushes

b) 6 brushes c) 3 brushes 475. In a 2 phase induction motor the control winding is fed with a) variable phase AC supply b) fixed AC supply # c) variable amplitude supply only 476. A 3 phase induction motor can be reversed by a) isolating one phase b) reversing the rotor connections # c) changing over any two phases 477. The speed of an AC motor can be affected by the a) field current # b) pairs of poles c) armature current 478. A generator rated at 30 KVA and power factor 0.8 has a maximum continuous power output of a) 30 kW # b) 24 kW c) 37.5 kW 479. An AC motor which rotates at the same speed as the supply frequency is called a) a universal motor b) an induction motor # c) a synchronous motor 480. In the circuit shown, impedance will be

#

a) 9 ohms b) 5 ohms c) 7 ohms

Page 62 – Mod 3 481. In the circuit shown, if the frequency is increased from zero to resonant frequency, the circuit current would

# a) increase b) decrease c) stay the same 482. The true power developed in this circuit is

# a) 12W b) 50W c) 20W 483. The filter shown is a

a) band stop filter # b) low pass filter c) high pass filter 484. An example of a paramagnetic material is # a) iron b) silver c) glass Page 63 – Mod 3 485. in a balanced Wheatstone bridge, across the centre of the bridge there is # a) no current flow b) no voltage present at either end

c) current and voltage at maximum 486. A 24V battery has an internal resistance of 1 ohm. When connected to a load, 12 amps flows. The value of the load is a) 12 ohms # b) 1 ohm c) 1/2 ohm 487. The property of a material to accept lines of flux is called # a) permeability b) reluctance c) retentivity 488. Armature reaction in a DC generator causes # a) MNA to move in the direction of rotation b) MNA to move in the opposite direction of rotation c) GNA to move in the direction of rotation 489. in a DC motor, B-EMF rises if the motor # a) speed rises b) speed falls c) load rises 490. Vibration in a magnet causes a) flux to increase # b) flux to decrease c) flux to stay the same 491. A high pass filter has # a) high impedance to low frequency, low impedance to high frequency b) high impedance to high frequency, low impedance to low frequency c) high impedance to both high and low frequency 492. What sort of wave would be used in a CR oscillascope to control sweep? # a) Sawtooth b) Square c) Sine wave

Page 64 – Mod 3 493. If there was a mainly inductive load on an AC generator, the voltage with respect to the current would # a) lead b) lag c) be in phase

494. on a brushless AC generator, the permanent magnet generator output is a) DC # b) AC c) pulsed 495. The output from a rotating armature AC generator would be taken from # a) the rotor b) the stator c) either the rotor or the stator 496. A frequency wild AC generator system has a) variable voltage and frequency # b) variable frequency only c) variable voltage only 497. in a series LCR circuit at resonance, R = 100 ohms, L and C are each 10 ohms. The total impedance is # a) 100 ohms b) 30 ohms c) zero ohms 498. An AC generator has four poles. To produce a frequency of 400Hz it must achieve a speed of a) 6000 RPM b) 8000 RPM # c) 12000 RPM 499. If an AC sinewave has an RMS value of 5V its peak value is a) 14.14 V b) 6.37 V # c) 7.07 V 500. The Daniel Cell electrodes are # a) copper and zinc b) carbon and zinc c) zinc and manganese dioxide

Page 65 – Mod 3 501. An inductor of resistance 5 k ohms and inductance 2mH is connected to a DC circuit. The time constant is # a) 400 ns b) 10 seconds c) 40 ms

502. The unit of flux is the # a) Weber b) Ampere turns c) Ampere turns / metre 503. The flux density of a magnetic field is 1.5T. The length of the conductor in the field is 2 m and the speed of the conductor is 10 m/s. The EMF induced is a) 0.3 V # b) 30 V c) 7.5 V 504. A DC generator armature has 6 poles and is lap wound. The number of brushes required are # a) 6 b) 2 c) 3 505. Reactive sparking is reduced by # a) interpoles b) compensating windings c) auxiliary windings 506. The back EMF in a DC motor is a) equal to the applied EMF # b) less than the applied EMF c) greater than the applied EMF 507. The flux density of a magnetic field is 1.5T. The length of the conductor in the field is 2 m and the current flowing through the conductor is 5 amps. The force on the conductor is # a) 15 Newtons b) 0.6 Newtons c) 3.75 Newtons 508. A DC shunt motor has 28 volts applied. The current taken from the armature of 2 ohms resistance is 1 amp. The BEMF is a) 30 V b) 27 V # c) 26 V

Page 66 – Mod 3 509. in a motor, armature reaction causes the MNA to move a) in the direction of rotation # b) against the direction of rotation c) to the GNA 510. A circuit with good selectivity will have

#

a) a large bandwidth b) a narrow bandwidth c) a low L/C ratio

511. Apparent power in an AC circuit is found by # a) V x I b) V x I x cosØ c) V x I x sinØ 512. A 300 ohm resistor would have a colour code of a) orange, orange, brown b) orange, brown, black # c) orange, black brown 513. in a synchronous motor, when the motor is running the slip is a) 100% b) 5% # c) 0% 514. In a two-phase induction motor there are a) 2 poles b) 3 poles # c) 4 poles 515. The diagram shown is a

a) short shunt compound wound machine # b) long shunt compound wound machine c) shunt wound machine Page 67 – Mod 3 516. A transformer has 500 turns on the primary and 100 turns on the secondary. When connected to a 100 V supply, the output is a) 500 V # b) 20 V c) 25 V

517. in the previous question, the secondary is connected to a 10 ohm load. The primary current is a) 10 amps # b) 0.4 amps c) 2 amps 518. Magneto motive force can be found by a) N/I # b) I x N c) Blv 519. Permeability of a material can be found by # a) flux density / MMF b) MMF x flux density c) MMF / flux density 520. A filter with a small bandwidth has # a) a high value of Q b) a low value of Q c) a Q of zero 521. A transformer has 1200 turns primary and 4800 turns secondary. What value of load resistance would be required to give a reflected impedance of 1000 ohms a) 1 kohm b) 4 kohm # c) 16 kohm 522. An autotransformer windings are a) on separate formers # b) connected c) wired in parallel 523. What voltage can the neutral line carry in a star transformer? a) Combined line voltages # b) Zero voltage c) Phase voltage 524. in a generator system, a stabilizing winding is used a) in series with the field to prevent oscillations # b) to prevent voltage overshoot c) to control output current Page 68 – Mod 3 525. When magnetizing a piece of material, magnetic strength will rise a) linearly with coercive force b) linearly with magnetic force # c) non-linearly with magnetic force 526. The stator of a permanent magnet rotor AC generator

#

a) is wound in series with the field b) is usually delta wound c) is usually star wound

527. In a resistive/inductive motor # a) the resistor circuit must be disconnected after starting b) is less efficient than a capacitor start motor c) can only be used for light loads 528. When a conductor is cut by magnetic lines of force an EMF is induced. This is a) Lenz's Law # b) Faraday's Law c) Kirchoff's Law 529. A 47K resistor has the following color code # a) Yellow, Violet, Orange b) Orange, Violet, Red c) Red, Orange, Yellow 530. A material with a narrow hysterisis loop a) has a high retentivity # b) has a low retentivity c) cannot be magnetised 531. The power output of a similar sized 3 phase compared to a single phase generator is a) less b) same # c) more 532. What part of a DC motor would you find the poles? a) brushes # b) stator c) rotor 533. in a high Q parallel resonant circuit, what happens to impedance if capacitance is increased by a factor of 4? # a) It reduces by 75% b) It remains the same c) It increases by factor of 4 Page 69 – Mod 3 534. In a thermocouple where is voltage measured? a) At the hot junction # b) At the cold junction c) At both junctions 535. Mercury cells are covered with a metal cover

#

a) as a protective cover b) as a positive terminal c) as a negative terminal

536. When switching off the supply, the back emf in a collapsing field in an inductor a) never exceeds forward emf # b) can be multiple times bigger than forward emf c) is equal to forward emf 537. If the energy supplied to a circuit for 4hrs 15 mins at 800 j/sec what would be the energy consumed? # a) 3.4 KW Hrs b) 3400 KW Hrs c) 340 KW Hrs 538. A parallel circuit at resonance has its impedance at a # a) maximum b) minimum c) zero 539. A parallel circuit with any number of 2 terminal connections a) has the same current throughout # b) the individual voltage drops is equal to the emf c) the resistance is dependent on current 540. In this circuit, Rx is equal to

#

a) R3 x R2 ÷ R4 b) R3 x R4 ÷ R2 c) R2 x R4 ÷ R3

Page 70 – Mod 3 541. A transformer to supply a 24V load with a 5:1 turn's ratio will have what primary supply? a) 120 VDC b) 48 VAC # c) 4.8 V 542. A material exposed to heat will

#

a) be harder to magnetise b) be easier to magnetise c) have no effect on magnetism

543. A 20 Pico farad capacitor with a 1MW resistor takes how long to charge? # a) 20 microseconds b) 0.1 second c) 10 seconds 544. A transformer has 2000V, 500 turns on the primary and 50 turns on the secondary. What would be the line voltage if the transformer were Delta/Star connected? a) 200V # b) 346V c) 450V 545. The main advantage of a starter-generator over conventional units is a) for the same power output there is a weight reduction and the starter drive remains engaged # b) for the same power output there is a weight reduction and the drive is constantly engaged c) it can produce a greater power output 546. The speed of a single phase induction motor is dependant on a) the strength of the field # b) the number of pairs of poles c) the strength of the armature current 547. An A.C. shunt wound motor sometimes uses a volts dropping resistor. The resistor would be # a) in series with the supply b) in series with the field c) in series with the armature 548. The time to fully charge a 1 micro farad capacitor in series with a 100K ohm resistor is # a) 100 ms b) 10 ms c)1 ms Page 71 – Mod 3 549. A sine wave has a periodic time of 0.5 milliseconds, what is its frequency? a) 200 Hz # b) 2Khz c) 20Khz 550. In a voltage equalizing circuit the generators are regulated so a) the lower output is increased to that of the higher

b) the higher output is decreased to that of the lower # c) the lower is increased and the higher is decreased until they are equal 551. The capacity of a battery is measured in a) volts b) cubic centimeters # c) ampere-hours 552. Phase angle is # a) the difference in degrees of rotation between 2 alternating voltages or currents or a voltage and a current b) the difference in degrees between the positive and negative parts of an ac sine wave c) the cosine of the peak value of an ac voltage 553. A battery's internal resistance is determined by # a) IR = OCV – CCV i b) IR = OCV + CCV i c) IR = OCV - CCV V 554. The impedance of an ac circuit is measured in a) kilovolt-amperes b) amperes # c) ohms 555. The formula for impedance in a series circuit is # a) b) c)

Page 72 – Mod 3 556. Motor slip is # a) the percentage of difference in speeds between the stator and rotor fields b) a shifting of the MNA of the motor c) a symptom of a weak field 557. The principal characteristic of a synchronous motor is

# a) it rotates at a speed that is synchronised with the applied ac current b) it must have a synchronised 3 phase supply to operate c) it rotates at a speed that is synchronised with the applied dc current 558. There are more negative than positive plates in a lead acid battery because # a) the positive plates are prone to warping if the chemical action is taking place only on one side b) it reduces the internal resistance of the cell c) it is necessary for chemical action to take place 559. Commutator ripple can be reduced by # a) the use of a ripple filter b) increasing generator frequency c) a resistor in series with the armature 560. In this circuit applied voltage is

# a) Vt = IXC b) Vt = IXL c) Vt = I/R 561. What is the internal resistance of a Leclanche cell? a) 6 ohms - 10 ohms # b) 0.02 ohms - 4 ohms c) 20 ohms - 30 ohms 562. In a DC motor the interpoles are part of the # a) field b) rotor assembly c) stator assembly Page 73 – Mod 3 563. The line voltage in a wye wound transformer is a) root 3 / phase voltage b) the same as phase voltage # c) root 3 x phase voltage 564. The valence electron is # a) the electron in outer shell of atom

b) the electron in inner shell of atom c) a positive electron 565. An aircraft battery on charge from the aircraft generators causes a) internal resistance of the battery to decrease in sympathy with the decreasing charging current # b)battery voltage to increases to nominal voltage and the charge current decreases c) battery voltage to decrease to zero until it is fully charged 566. What happens to the current in a series resistive resonant circuit? # a) It is maximum b) It is minimum c) It is zero 567. An atom with a deficiency in electrons has a) high resistance # b) low resistance c) high impendence 568. What effect does hydrogen have in a battery cell? # a) Polarization b) Sulphation c) Nothing 569. Eddy current losses in a transformer are a) current used in magnetising the core # b) current flow induced into the core c) hysteresis losses 570. A 3-phase star-delta wound transformer gives a) 90° phase shift b) no phase shift # c) 30° phase shift 571. In a parallel circuit containing resistors # a) the voltage is the same in all parts of the circuit b) the sum of the voltage drops equals applied voltage c) resistance is determined by value of current flow

Page 74 – Mod 3 572. An induced current in a coil # a) opposes the EMF producing it b) aids the EMF producing it c) does not affect the EMF producing it 573. Armature reaction is a) reactive sparking

#

b) due to dirty or worn commutator c) the MMF opposing rotation

574. in a 4:1 step up transformer, what would give a reflected impedance of 1K ohm a) 1 k ohm b) 4k ohm # c) 16k ohm 575. Lines of magnetic flux pass from # a) N to S b) E to W c) S to N 576. A shunt motor a) gives constant torque with variations in speed # b) is constant speed c) has high starting torque 577. The direction of current in a wire rotating in a magnetic field can be determined by # a) Fleming's right hand rule b) Fleming's left hand rule c) cork screw rule -----578. The diagram shows a 200V long shunt generator. What is the voltage across the series resistor? a) 30V # b) 6V c) 10V 579. in a parallel LCR circuit, if the capacitance is increased by 4 times, what happens to the impendence? a) increases by 4 times # b) decreases by 75% c) remains the same 580. in a DC shunt motor, if the field resistance is increased what happens to the back EMF? a) increases # b) decreases c) remains the same Page 75 – Mod 3 581. Why is ferrite used in memory circuits? # a) High remanence b) Low permeability c) High reluctance 582. What semi-conductor material is used in memory circuits? # a) Ferrite

b) Permeomag c) Iron 583. The discharge curve of a capacitor is a) Linear b) Logarithmic # c) Exponential 584. to generate electricity with a fuel cell, you need a constant supply of # a) Oxygen & Hydrogen b) Kerosene & Heat c) Nitrogen & Sunlight 585. Five different value resistors all have the same voltage dropped across them, how are the resistors connected? a) In Series # b) In Parallel c) In Series/Parallel ----- 586. The input is 115V and is applied across the 300 turn portion. What is the output? # a) 460V b) 115V c) 28V 587. A near perfect 4:1 step up transformer has it's primary connected to 120VAC, if the secondary is connected to a load with 1600 ohms resistance what is the current in the primary a) 1 amp b) 0.3 amps # c) 1.2 amps 588. Flux losses in a transformer can be prevented by a) the use of primary shielding # b) winding the primary on top of the secondary c) laminating the core

Page 76 – Mod 3 589. A ni-cad battery found to be below normal capacity should a) be removed and used for ground use only # b) be re-charged with a freshening charge c) have its electrolyte adjusted 590. In cold weather a battery must be kept # a) fully charged

b) fully discharged c) does not matter 591. A simple basic induction motor has # a) poor starting torque, good running torque b) good starting torque, poor running torque c) poor starting torque, poor running torque 592. If the frequency to a capacitor increases, the current through it # a) is zero b) increases c) decreases 593. In a 3-phase delta wound circuit, line current is a) same as the phase current b) in phase with the phase current # c) the vectorial sum of all 3 phase currents 594. Conductance of a circuit is 2 milliMhos. What is its resistance? a) 5 MegaOhms # b) 500 Ohms c) 5000 Ohms 595. To increase the voltage output of a generator you can # a) increase speed b) decrease speed c) It is not speed dependant 596. How would you find the direction of the current flow in an armature located in a magnetic field? a) Maxwells corkscrew rule # b) Flemings right hand rule c) Fleming's left hand rule 597. If in a electrical circuit there is a difference between the capacitive reactance and the inductive reactance, what would the power factor of the circuit be? a) Unity # b) Less than unity c) More than unity Page 77 – Mod 3 598. What is the SI unit of conductance? # a) Sieman b) Ohm c) Ohm-metre 599. What is the SI unit of resistivity? # a) Ohm metre

b) Ohms/metre c) Ohms 600. Generator voltage is # a) dependant on speed of rotation b) independent of speed of rotation c) not dependant on speed of rotation 601. If a negatively charged conductor is placed next to an insulated rod a) the rod has no charge b) the rod becomes negatively charged # c) the rod becomes positively charged 602. What is the formula for conductance? # a) 1/R b) 1 - R c) R + 1 603. What happens if you reverse the supply to the field and armature of a DC shunt motor? a) Reverses direction of rotation # b) Continues to rotate in same direction c) Fails to start 604. The internal resistance of a battery off load compared to on load is # a) same b) increased c) decreased 605. What is the rating of a monolithic capacitor with 103 on it # a) 10000pf b)100000pf c) 1000pf 606. What is the formula for working out the capacitance of a capacitor if K = dielectric constant, A = area of the plates, d = distance plates apart? # a) c = KA/d b) c = Kd/A c) c = d/KA

Page 78 – Mod 3 607. 115V RMS 2.5A at 60 degrees what is the power disipated? a) 79 W # b) 143 W c) 300 VA 608. If cobalt has a permeability of 4800 it is a # a) ferromagnetic

b) paramagnetic c) diamagnetic 609. The output from a generator to a commutator is # a) AC b) DC c) pulsed DC 610. When light hits a photodiode resistance a) increases # b) decreases c) stays the same 611. What type of wave is it when the vertical and horizontal distances are equal? # a) Square b) Rectangular c) Sawtooth 612. Cobalt has permeability # a) greater than unity b) same as unity c) less than unity 613. In an aircraft brushless alternator the armature is a) in series with the field # b) star wound c) delta wound 614. to supply a 24 volt output with a transformer with a 5:1 turns ratio, the input required is a) 120V # b) 4.8V c) 24V 615. in a resonant parallel circuit, current is a) max # b) min c) zero

Page 79 – Mod 3 616. Total capacitance of 3 capacitors each 12mF in a parallel circuit # a) 36mF b) 12mF c) 6mf 617. Band stop filter # a) attenuates frequencies in a specified narrow band

b) stops frequencies in a narrow band c) pass all frequencies in that band 618. A combination of 1 megohm and 8 microfarad would give a time constant of a) 40 seconds # b) 8 seconds c) 400 ms 619. Power factor is a) sin theta # b) cos theta c) tan theta 620. What is the main disadvantage of a starter generator? a) Will not supply output at low rpm # b) Heavier than like for like c) Can only be used on piston engines 621. What is the voltage across a fully charged capacitor? # a) Same as circuit voltage b) Less than circuit voltage c) More than circuit voltage 622. When would you use an electrolytic capacitor? a) On a balanced circuit # b) Large output compared to size required c) Low output compared to size required 623. If the phase voltage of a star wound generator is 115V, what would be the line-to-line voltage? # a) 200V b) 180V c) 220V 624. Back-EMF is the greatest when a motor is # a) at operating speed b) just starting to rotate c) under heavy load

Page 80 – Mod 3 625. What are the factors affecting the frequency of an ac generator? a) Number of turns in the armature coil and rpm # b) Number of pole pairs and rpm c) Number of turns in the armature coil and number of pole pairs 626. Which of the following applications would require a "continuously rated" motor

#

a) Flap drive actuator b) Fuel pump motor c) Cargo door actuator

627. What would you use for the core in a generator current transformer? # a) Air core b) Laminated core c) Steel Core 628. Spontaneous magnetisation occurs in a a) permomagnet # b) ferromagnet c) diamagnet 629. An aircraft transformer is needed to step up a voltage. What sort would be used a) Air core # b)Laminated core c) Solid core 630. A conductor is placed in a magnetised coil. What will happen a) A force will be created # b) Nothing will happen unless the conductor is moved c) The conductor will move 631. An atom with less than 4 electrons in its outer shell has # a) low electrical resistance b) high electrical resistance c) no electrical resistance 632. in a 4:1 step-up transformer, 120V is applied to the primary, and the load on the secondary is 1600 Ohms. What is the current in the primary? a) 0.075A # b) 1.2A c) 3A 633. Two 12V, 40Ah cells in series gives # a) 24V 40Ah b) 24V 80Ah c) 12V 40Ah Page 81 – Mod 3 634. A 2 Megohm resistor can be written a) M20F # b) 2M0F c) 20MF 635. If a resistor is too small or misshapen to fit the colour code bands, how else is it's value indicated?

#

a) Dots b) Letter code c) Number code

636. Elements such as phosphorus with 5 electrons in their outer shell, when combined with pure silicon, is a # a) donor b) acceptor c) isotopic -------- 637. This is a diagram of a # a) Light Dependant Resistor b) Logarithmic Differential Resistor c) Laser Diode Rectifier 638. A centrifugal speed switch is used # a) to cut out the resistor/inductor circuit on an AC motor b) to cut out the capacitor circuit on an AC motor c) to cut in the resistor/inductor circuit on an AC motor 639. Disconnecting one of the phases from a 3-phase motor will cause the motor to a) stop b) run a 2/3 speed # c) run at the same speed 640. To find the internal resistance of a battery in a circuit of known current a) use the formula R = V x I # b) find the lost volts of the circuit c) find the EMF of the circuit

Page 82 – Mod 3 Ahmed Marafi 26569