Electrics
Electrics
I.
I.
Direct current (DC)
Direct current (DC)
II.
II.
Alternating current (AC)
Alternating curre
nt (AC)
III.
III.
Semiconductors
Semiconductors
IV.
IV.
Basic knowledge of computers
Basic knowledge of computers
V.
Direct current (DC):
Direct current (DC):
A component consuming 80 watts at 8 amps
A component consuming 80 watts at 8 amps would require a supply of:would require a supply of: A) 5 Volts A) 5 Volts B) B) 0,01 kV 0,01 kV C) 100 Volts C) 100 Volts D) 0.008 kV D) 0.008 kV In an aeroplane utilising
In an aeroplane utilising a constant frequency AC power supply, DC power is obtained from a:a constant frequency AC power supply, DC power is obtained from a: A) rotary converter.
A) rotary converter. B) static inverter. B) static inverter. C)
C) 3 phase current transformer 3 phase current transformer unit.unit. D)
D) T Transformer Rectifier Unit.ransformer Rectifier Unit. Aircraft standard fuses are fitted to: Aircraft standard fuses are fitted to: A) AC circuits.
A) AC circuits.
B) DC circuits only. B) DC circuits only. C)
C) protect wiring in battery circuits protect wiring in battery circuits only.only. D)
D) DC and AC DC and AC circuits.circuits. A 24V, 60 Ah battery is
A 24V, 60 Ah battery is driving a 48 Watts light driving a 48 Watts light bulb. Approximately how long would the battery lastbulb. Approximately how long would the battery last assuming that it is new?
assuming that it is new? A) 120 hours. A) 120 hours. B) B) 30 hours. 30 hours. C) 60 hours. C) 60 hours. D) 2,5 hours. D) 2,5 hours.
Two resistors with values of 6 Ohm and 100 Ohm
Two resistors with values of 6 Ohm and 100 Ohm are connected in parallel. Their combined resistance is:are connected in parallel. Their combined resistance is:
A)
A) 5,66 Ohm. 5,66 Ohm. B) 94 Ohm. B) 94 Ohm. C) 106 Ohm. C) 106 Ohm. D) 0,177 Ohm. D) 0,177 Ohm.
Magnetism can be used to generate electricity by
Magnetism can be used to generate electricity by converting mechanical energy to electrical energyconverting mechanical energy to electrical energy by:
by:
A) electro magnetic conversion. A) electro magnetic conversion. B)
B) electr electro magnetic o magnetic induction.induction. C) electro motive force.
C) electro motive force. D) electro self induction. D) electro self induction. The operating principle of a fuse is: The operating principle of a fuse is: A)
A) a wire with a wire with a predetermined melting point.a predetermined melting point. B) a relay.
B) a relay.
C) a bimetallic strip. C) a bimetallic strip.
D) a high resistance metal wire. D) a high resistance metal wire.
Bonding is used to protect the aircraft against fire by: Bonding is used to protect the aircraft against fire by: A) providing an earth return system. A) providing an earth return system. B)
B) ensuring the same electrical potential of all metal components in the ensuring the same electrical potential of all metal components in the aircraft's structure.
aircraft's structure.
C) provision of an independent ignition system. C) provision of an independent ignition system.
D) maintaining a different electrical potential throughout the aircraft's D) maintaining a different electrical potential throughout the aircraft's
structure. structure.
If the power being drawn by a
If the power being drawn by a resistor is 100 watts from a 50V supply, what resistor is 100 watts from a 50V supply, what is the resistance of is the resistance of thethe load? load? A) 50 Ohms. A) 50 Ohms. B) B) 25 Ohms. 25 Ohms. C) 2 Ohms. C) 2 Ohms. D) 4 Ohms. D) 4 Ohms.
The commutator of a DC generator converts: The commutator of a DC generator converts: A) DC to AC A) DC to AC B) AC to AC at a different voltage B) AC to AC at a different voltage C) C) AC to DC AC to DC D) DC to AC at a different voltage D) DC to AC at a different voltage In the following diagram A, B and C are In the following diagram A, B and C are respectively the:
respectively the:
A) battery master switch, starter A) battery master switch, starter
relay, starter switch. relay, starter switch.
B) starter switch, battery master B) starter switch, battery master
switch, starter relay. switch, starter relay. C)
C) batt battery master swery master switch, starteritch, starter switch, starter relay.
switch, starter relay.
D) starter relay, starter switch, D) starter relay, starter switch,
battery master switch. battery master switch.
Recharging an aircraft's battery from an AC system would require: Recharging an aircraft's battery from an AC system would require: A)
A) a TRU. a TRU.
B) an inverter. B) an inverter. C)
C) nothing since the battery can supply AC as well.nothing since the battery can supply AC as well. D) a rectifier.
D) a rectifier.
A rotary valve actuator is in the closed position. Its 'OPEN' limit switch is... and its 'CLOSE' limit switch A rotary valve actuator is in the closed position. Its 'OPEN' limit switch is... and its 'CLOSE' limit switch is...
is...
A) open, closed A) open, closed B)
B) closed, open closed, open C) open, open C) open, open D) closed, closed D) closed, closed
When a battery is almost fully discharged there is a tendency for the: When a battery is almost fully discharged there is a tendency for the: A) electrolyte to " boil" .
A) electrolyte to " boil" . B)
B) current produced to increase due to the reduced voltage.current produced to increase due to the reduced voltage. C)
C) voltage to increase due to voltage to increase due to the current available.the current available. D)
D) voltage to voltage to decrease under load.decrease under load. With regards to a light
With regards to a light aircraft electrical system, where is the generator switch normally located?aircraft electrical system, where is the generator switch normally located? A) In series with the armature.
A) In series with the armature.
B) In series with the cut-out switch. B) In series with the cut-out switch. C)
C) In series with In series with the field winding.the field winding. D) In parallel with the field winding. D) In parallel with the field winding. The purpose of a battery protection unit
The purpose of a battery protection unit is generally to isolate the battery:is generally to isolate the battery: 1.
1. from the bus when tfrom the bus when t he battery charge is deemed satisfactoryhe battery charge is deemed satisfactory 2.
2. when there is a when there is a battery overheat conditionbattery overheat condition 3.
3. in case of an internal short circuitin case of an internal short circuit 4.
4. in case of a fault in case of a fault on the ground power uniton the ground power unit The combination which regroups all of the
The combination which regroups all of the correct statements is :correct statements is : A) 1, 2 A) 1, 2 B) 1, 2, 3, 4 B) 1, 2, 3, 4 C) C) 1, 2, 3 1, 2, 3 D) 1 D) 1
In order that DC generators will achieve equal
In order that DC generators will achieve equal load sharing when operating in parallel, it load sharing when operating in parallel, it is necessaryis necessary to ensure that:
to ensure that: A)
A) their voltages are almost their voltages are almost equal.equal. B)
B) the synchronising bus-bar is disconnected from the busbar system.the synchronising bus-bar is disconnected from the busbar system. C)
C) equal loads are connected to each generator busbar before paralleling.equal loads are connected to each generator busbar before paralleling. D) adequate voltage differences exists.
D) adequate voltage differences exists. The power dissipated as heat by a
The power dissipated as heat by a resistance R with an applied voltage V resistance R with an applied voltage V carrying a current I can becarrying a current I can be expressed as: expressed as: A) V x V / I. A) V x V / I. B) B) I x I I x I x R.x R. C) I x I / V. C) I x I / V. D) I x R x R. D) I x R x R.
Aircraft systems are almost always: Aircraft systems are almost always: A)
A) ear earth return th return systemssystems B)
B) earth return with static system emergency back upearth return with static system emergency back up C) single pole static systems
C) single pole static systems D) dipole systems
An aircraft has total
An aircraft has total services drawing 120 amps, essential services drawing 45 amps and vital servicesservices drawing 120 amps, essential services drawing 45 amps and vital services drawing 5 amps. The designer has 50 Ah
drawing 5 amps. The designer has 50 Ah capacity batteries (at system voltage) available and wishescapacity batteries (at system voltage) available and wishes to ensure that the aircraft can fly safely for at least
to ensure that the aircraft can fly safely for at least 2 hours following a breakdown of electric2 hours following a breakdown of electricalal generators. What configuration of
generators. What configuration of batteries would be employed?batteries would be employed? A) 3 in series. A) 3 in series. B) 3 in parallel. B) 3 in parallel. C) 6 in parallel. C) 6 in parallel. D) D) 2 in 2 in parallel.parallel. 21.
21.Impedance is:Impedance is: A)
A) the combined effect of the combined effect of resistance and reactance.resistance and reactance. B)
B) the combined effect of real and imaginary power.the combined effect of real and imaginary power. C)
C) the combined effect of resistance and conductivity.the combined effect of resistance and conductivity. D) the combined effect of power factor and
D) the combined effect of power factor and phase angle.phase angle. Consider a battery voltage V, connected to R1 and R2
Consider a battery voltage V, connected to R1 and R2 which are in parallel: If which are in parallel: If V is 250 volts, R1 iV is 250 volts, R1 i s 500s 500 Ohms but R2 is
Ohms but R2 is a very low resistance then:a very low resistance then:
A) The total current from the battery will approximate the current in R1. A) The total current from the battery will approximate the current in R1. B) R2 is insignificant.
B) R2 is insignificant. C)
C) A large total A large total current will flow.current will flow. D) A small total current will flow. D) A small total current will flow. A generator is taken Off-line by:
A generator is taken Off-line by: A)
A) operating the field operating the field switchswitch B)
B) manual operation of the generator cut-outmanual operation of the generator cut-out C) removing all loads
C) removing all loads
D) creating a short circuit. D) creating a short circuit.
Electrical batteries when connected in parallel provide... amp/hr capacity and... voltage. Electrical batteries when connected in parallel provide... amp/hr capacity and... voltage. A)
A) increase increased; the d; the samesame B) reduced; increased B) reduced; increased C) the same; increased C) the same; increased D) increased; reduced D) increased; reduced
The international symbol of electrical power is The international symbol of electrical power is A) U and it is measured in volts. A) U and it is measured in volts. B)
B) P and it is measured in watts. P and it is measured in watts. C) R and it is measured in ohms. C) R and it is measured in ohms. D) I and it is measured in amperes. D) I and it is measured in amperes. The capacity of a
The capacity of a battery is expressed in terms of:battery is expressed in terms of: A) internal resistance. A) internal resistance. B) watts. B) watts. C) volts. C) volts. D) D) ampere-hours. ampere-hours.
A 12 volt battery that has 1 dead cell: A 12 volt battery that has 1 dead cell: A) has less capacity.
A) has less capacity. B)
B) is unserviceable. is unserviceable.
C) still has a voltage of 12V. C) still has a voltage of 12V.
D) has its capacity reduced by 1/12th. D) has its capacity reduced by 1/12th. When an electrical circuit is open circuited:
When an electrical circuit is open circuited: A) resistance will be low
A) resistance will be low B) resistance will be zero B) resistance will be zero
C) components will operate normally C) components will operate normally D)
D) resistance will be resistance will be highhigh The unit of inductance is:
The unit of inductance is: A) the Farad. A) the Farad. B) the Reactance. B) the Reactance. C) the Ohm. C) the Ohm. D)
D) the Henry. the Henry.
The inductance of several inductors connected in series can
The inductance of several inductors connected in series can be calculated to be:be calculated to be: A)
A) the sum of the individual inductances divided by the number of inductors.the sum of the individual inductances divided by the number of inductors. B)
B) the sum of the individual inductances. the sum of the individual inductances.
C) the inverse of the sum of the individual inductances. C) the inverse of the sum of the individual inductances. D) the inverse of the sum of the inv
D) the inverse of the sum of the inverses of the individual inductances.erses of the individual inductances. The purpose of the voltage regulator is to:
The purpose of the voltage regulator is to: A) Keep a
A) Keep a constant power output from the generatorconstant power output from the generator B) Keep a constant frequency
B) Keep a constant frequency C)
C) Keep a constant vKeep a constant voltage output from the oltage output from the generatorgenerator D) Keep a constant current output from the generator D) Keep a constant current output from the generator
What unit is used to measure potential difference between two points in an electrical circuit? What unit is used to measure potential difference between two points in an electrical circuit? A) Ohm A) Ohm B) Amps B) Amps C) C) Volts Volts D) Coulombs D) Coulombs
True power is measured in: True power is measured in: A) Kilovolt-amperes. A) Kilovolt-amperes. B) Kilovolt-amperes-reactive. B) Kilovolt-amperes-reactive. C) Kilojoules. C) Kilojoules. D) D) Kilowatts. Kilowatts.
When fully charged, what is
When fully charged, what is the maximum voltage across a lead-acid cell?the maximum voltage across a lead-acid cell? A) 24 volts. A) 24 volts. B) B) 2.2 volts. 2.2 volts. C) 2 volts. C) 2 volts. D) 12 volts. D) 12 volts.
In a supply system which i
In a supply system which i s AC, DC requirements are provided by:s AC, DC requirements are provided by: A) rotary inverter. A) rotary inverter. B) B) TRU's. TRU's. C) batteries. C) batteries. D) a static inverter. D) a static inverter.
In normal conditions, generator output voltage is arranged to be: In normal conditions, generator output voltage is arranged to be: A) as high as possible
A) as high as possible
B) exactly the same as battery voltage B) exactly the same as battery voltage C) less than battery voltage
C) less than battery voltage D)
D) higher then battery higher then battery voltagevoltage
An ammeter indicates a high rate of charge after engine start. This... An ammeter indicates a high rate of charge after engine start. This... A)
A) is dangerous. The field circuit breakeis dangerous. The field circuit breaker should be tripped manually.r should be tripped manually. B)
B) is dangerous. The engine shois dangerous. The engine should be shut down immediately.uld be shut down immediately. C) indicates generator failure.
C) indicates generator failure. D)
D) is only allowed is only allowed for a short period.for a short period. Fuses are rated to a value by:
Fuses are rated to a value by: A)
A) the number of amperes the number of amperes they will carrythey will carry B) their wattage
B) their wattage C)
C) the number of volts they will passthe number of volts they will pass D) their resistance measured in ohms D) their resistance measured in ohms
The connection in series of two 12 volt / 40 amp hours batteries, will create a unit with the following The connection in series of two 12 volt / 40 amp hours batteries, will create a unit with the following characteristics:
characteristics:
A) 24 volt / 80 amp hours A) 24 volt / 80 amp hours B) 12 volt / 80 amp hours B) 12 volt / 80 amp hours C)
C) 24 volt / 24 volt / 40 amp hours40 amp hours D) 12 volt / 40 amp hours D) 12 volt / 40 amp hours Usually, in conductive materials: Usually, in conductive materials: A)
A) the resistance decreases with increasing temperature.the resistance decreases with increasing temperature. B)
B) the resistance increases with the resistance increases with increasing temperature.increasing temperature. C) resistance and temperature are not related.
C) resistance and temperature are not related.
D) the resistance remains constant regardless of temperature. D) the resistance remains constant regardless of temperature.
41.
41. When carrying out battery condition check using the aeroplane’ s voltmeter:When carrying out battery condition check using the aeroplane’ s voltmeter: A)
A) no load should be applied to the battery because it would depress theno load should be applied to the battery because it would depress the voltage.
voltage.
B) the battery should be isolated. B) the battery should be isolated. C) the load condition is unimportant. C) the load condition is unimportant. D)
D) a load should be applied a load should be applied to the battery in order to give a to the battery in order to give a better indicationbetter indication of condition.
of condition.
The total current flow in an electrical circuit with resistors in parallel is equal to... The total current flow in an electrical circuit with resistors in parallel is equal to... A)
A) the sum of all the currents in all the components divided by the numberthe sum of all the currents in all the components divided by the number of components.
of components. B)
B) the reciprocal of the the reciprocal of the sum of the current rsum of the current reciprocals.eciprocals. C)
C) the sum of all the the sum of all the current reciprocals.current reciprocals. D)
D) the sum of all the currents in the sum of all the currents in all the components in the circuit.all the components in the circuit. What are fuses rated in?
What are fuses rated in? A) Watts. A) Watts. B) Volts. B) Volts. C) Ohm. C) Ohm. D) D) Amps. Amps.
Apparent Power is measured in: Apparent Power is measured in: A) KWR or WR.
A) KWR or WR. B) KW or Watts. B) KW or Watts. C)
C) KVA or VA. KVA or VA. D) KVAR of VAR. D) KVAR of VAR.
An aircraft electrical circuit which uses
An aircraft electrical circuit which uses the aircraft structure as a the aircraft structure as a return path to earth, may be return path to earth, may be defineddefined as a
as a A)
A) single pole single pole circuitcircuit B) semi-negative system B) semi-negative system C) double pole circuit C) double pole circuit
D) complete negative system D) complete negative system
Voltage is proportional to rate of change of current in a: Voltage is proportional to rate of change of current in a: A) resistor. A) resistor. B) B) inductor. inductor. C) capacitor. C) capacitor. D) battery. D) battery. In a DC
In a DC generator circuit the reverse current relay:generator circuit the reverse current relay: A)
A) prevents the battery from prevents the battery from too high a charging rate.too high a charging rate. B)
B) allows current to flow in both directions through the generator.allows current to flow in both directions through the generator. C)
C) allows the charge rate to drop as the battery becomes charged.allows the charge rate to drop as the battery becomes charged. D)
D) prevents the battery from prevents the battery from motoring the generator at lmotoring the generator at low speeds andow speeds and when stationary.
Voltage is: Voltage is: A)
A) is also known is also known as potential differenceas potential difference B) an electro motive force
B) an electro motive force C)
C) a measure of the electrical charge passing a pointa measure of the electrical charge passing a point D) a measure of the power gained
D) a measure of the power gained
The difference in electrical potential in a circuit is measured in: The difference in electrical potential in a circuit is measured in: A) Amperes. A) Amperes. B) B) Volts. Volts. C) Watts. C) Watts. D) Joules. D) Joules.
When does a generator cut-out open? When does a generator cut-out open? A)
A) When generator voltage exceeds a certain value.When generator voltage exceeds a certain value. B)
B) When battery voltage exceeds When battery voltage exceeds generator voltage.generator voltage. C) When generator voltage exceeds battery voltage. C) When generator voltage exceeds battery voltage. D) When battery voltage exceeds a certain level. D) When battery voltage exceeds a certain level. On a self-exited DC generator, if
On a self-exited DC generator, if the voltage regulator increases the current through the field windingsthe voltage regulator increases the current through the field windings then:
then: A)
A) The intensity of the field decreases and the output voltage increases.The intensity of the field decreases and the output voltage increases. B)
B) The intensity of the field increases and the output voltage increases. The intensity of the field increases and the output voltage increases. C) The intensity of the field increases and the output voltage decreases. C) The intensity of the field increases and the output voltage decreases. D) The intensity of the field decreases and th
D) The intensity of the field decreases and the output voltage decreases.e output voltage decreases. The capacity of a typical lead acid battery for aviation use is
The capacity of a typical lead acid battery for aviation use is A) 4-8 Ah. A) 4-8 Ah. B) 24 V. B) 24 V. C) 12 Volts C) 12 Volts D) D) 12-18 Ah. 12-18 Ah.
The power in a direct current circuit is equal to: The power in a direct current circuit is equal to: A) R x I x V A) R x I x V B) B) V x I V x I C) V x R C) V x R D) I x R D) I x R
The total current in a parallel circuit is equal to: The total current in a parallel circuit is equal to: A)
A) the sum of all the currents of all the components, divided by the numberthe sum of all the currents of all the components, divided by the number of components
of components B)
B) the sum of the curthe sum of the current reciprocalsrent reciprocals C)
C) the reciprocal of the sum of the current reciprocalsthe reciprocal of the sum of the current reciprocals D)
Voltage is a measure of: Voltage is a measure of: A) coulombs per joule. A) coulombs per joule. B)
B) potential differential. potential differential. C) current.
C) current.
D) resistance to current. D) resistance to current.
The voltage regulator of a DC generator is
The voltage regulator of a DC generator is connected in:connected in: A)
A) parallel with the armature and in parallel with the shunt field.parallel with the armature and in parallel with the shunt field. B)
B) parallel with the armature and in series with the shunt field. parallel with the armature and in series with the shunt field. C) in series wi
C) in series with the armature and in parallel with the shunt field.th the armature and in parallel with the shunt field. D) series with the armature and in series with the shunt field. D) series with the armature and in series with the shunt field. A simple circuit has
A simple circuit has 4 amps flowing through a 5 4 amps flowing through a 5 ohm resistor. How much power is being used?ohm resistor. How much power is being used? A) 20 watts. A) 20 watts. B) B) 80 watts. 80 watts. C) 100 watts. C) 100 watts. D) 60 watts. D) 60 watts.
The connection in parallel of two 12 volt / 40 amp hours batteries, will create a unit with the following The connection in parallel of two 12 volt / 40 amp hours batteries, will create a unit with the following characteristics:
characteristics:
A) 24 volt / 40 amp hours A) 24 volt / 40 amp hours B) 24 volt / 80 amp hours B) 24 volt / 80 amp hours C)
C) 12 volt / 12 volt / 80 amp hours80 amp hours D) 12 volt / 40 amp hours D) 12 volt / 40 amp hours
The capacitance of several capacitors connected in series is equal The capacitance of several capacitors connected in series is equal to:to: A) the sum of the individual capacitances.
A) the sum of the individual capacitances. B)
B) the sum of the individual capacitances divided by the sum of the individual capacitances divided by the number ofthe number of capacitors.
capacitors. C)
C) the inverse of the the inverse of the sum of the individual capacitances.sum of the individual capacitances. D)
D) the inverse of the sum of the inverses of the inverse of the sum of the inverses of the individual capacitances.the individual capacitances. An Electromotive Force (EMF) can be measured with:
An Electromotive Force (EMF) can be measured with: A) a Hall effect probe.
A) a Hall effect probe. B) an ohmmeter.
B) an ohmmeter. C) an ammeter. C) an ammeter. D)
D) a voltmeter. a voltmeter.
61.
61.A spill of electrolyte from a A spill of electrolyte from a NiCad battery onto someone's skin should be:NiCad battery onto someone's skin should be: A) rinsed with a weak alkali (e.g. potassium hydroxide) A) rinsed with a weak alkali (e.g. potassium hydroxide) B) rinsed with a concentrated acid (e.g. sulphuric)
B) rinsed with a concentrated acid (e.g. sulphuric) C)
C) rinsed with a weak acid (e.g. boric acid). rinsed with a weak acid (e.g. boric acid).
D) rinsed with water and add sodium bicarbonate D) rinsed with water and add sodium bicarbonate
Resistance is expressed in... and the basic SI units for it are... Resistance is expressed in... and the basic SI units for it are... A)
A) Oh Ohms, V/Ams, V/A B) Ohms, R B) Ohms, R C) Ohms, J/C C) Ohms, J/C D) Farad, F D) Farad, F
Voltmeters and ammeters usually indicate: Voltmeters and ammeters usually indicate: A) amplitudes. A) amplitudes. B) mean values. B) mean values. C) peak-to-peak values. C) peak-to-peak values. D) D) RMS values. RMS values.
Current is expressed in... and the basic SI units for it are... Current is expressed in... and the basic SI units for it are... A) Coulombs, A/s A) Coulombs, A/s B) B) Amperes, C/s Amperes, C/s C) Amperes, kg/s C) Amperes, kg/s D) Farad, A/s D) Farad, A/s Batteries are rated in: Batteries are rated in: A) Henry A) Henry B) Joule B) Joule C) Volts C) Volts D)
D) Ampere hours and Ampere hours and VoltsVolts Which unit is
Which unit is commonly used for reactive power?commonly used for reactive power? A) kWR. A) kWR. B) B) kVAR. kVAR. C) kVA. C) kVA. D) kW. D) kW.
What is the purpose of a battery cut-out? What is the purpose of a battery cut-out? A)
A) to connect the battery to the starter motor when starting the engineto connect the battery to the starter motor when starting the engine.. B)
B) to open when the bto open when the battery is fully charged.attery is fully charged. C)
C) to prevent the battery discharging to the bus-bar when the generator isto prevent the battery discharging to the bus-bar when the generator is on-line.
on-line. D)
D) to prevent the battery to prevent the battery discharging into the discharging into the generator.generator. The so called HOT BUSSES or DIRECT BUSSES are:
The so called HOT BUSSES or DIRECT BUSSES are:
A) automatically connected to the battery if generators have failed A) automatically connected to the battery if generators have failed
B) kept in operating conditions by an electrical resistance in the case of B) kept in operating conditions by an electrical resistance in the case of
energy failure energy failure C)
C) directly connected to the directly connected to the batterybattery D) providing an alternative current D) providing an alternative current
On an aircraft with an earth return electrical system: On an aircraft with an earth return electrical system: A)
A) one lead of the one lead of the battery and one battery and one lead of the electrical lead of the electrical components arecomponents are connected to the aircraft structure
connected to the aircraft structure B)
B) the static electricity is discharged through the tyres on landingthe static electricity is discharged through the tyres on landing C)
C) one lead of all electrical components is earthed and the other isone lead of all electrical components is earthed and the other is connected to the bonding system
connected to the bonding system
D) the static electricity is discharged through a chain linkage dangled from D) the static electricity is discharged through a chain linkage dangled from
the ram air turbine under emergency conditions the ram air turbine under emergency conditions The type of windings commonly used in
The type of windings commonly used in DC starter motors are:DC starter motors are: A)
A) series wound. series wound.
B) series shunt wound. B) series shunt wound. C) shunt wound.
C) shunt wound.
D) compound wound. D) compound wound.
Consider a battery voltage V, connected to four resistors R1, R2, R3,
Consider a battery voltage V, connected to four resistors R1, R2, R3, R4. They are connected as twoR4. They are connected as two pairs in parallel (R1 and
pairs in parallel (R1 and R2, R3 and R4). The two R2, R3 and R4). The two pairs are connected in series: If R1 pairs are connected in series: If R1 and R2 are bothand R2 are both 8 Ohms, R3 is 6 Ohms, R4 is 3 Ohms, the total resistance of the circuit is:
8 Ohms, R3 is 6 Ohms, R4 is 3 Ohms, the total resistance of the circuit is: A) 25 Ohms. A) 25 Ohms. B) 6.16 Ohms. B) 6.16 Ohms. C) 5.33 Ohms. C) 5.33 Ohms. D) D) 6 Ohms. 6 Ohms.
Consider a battery voltage V, connected to three resistors R1, R2, R3. R2 and
Consider a battery voltage V, connected to three resistors R1, R2, R3. R2 and R3 are in parallel withR3 are in parallel with one another, and the combination of them is in series with R1. If R1 is 2 Ohms and has
one another, and the combination of them is in series with R1. If R1 is 2 Ohms and has 6 volts across6 volts across it, R2 has 2 amps running through it and R3 is 6 Ohms, what is
it, R2 has 2 amps running through it and R3 is 6 Ohms, what is R2?R2? A)
A) 3 Ohms. 3 Ohms. B)
B) Impossible to tell without also knowing total current from the battery.Impossible to tell without also knowing total current from the battery. C) Impossible to tell without knowing V.
C) Impossible to tell without knowing V. D) 6 Ohms.
D) 6 Ohms.
When refuelling an aircraft: When refuelling an aircraft: A)
A) the bonding plug must be connected to the earth terminal.the bonding plug must be connected to the earth terminal. B)
B) the refuelling nozzle must be bonded to the fuel tank. the refuelling nozzle must be bonded to the fuel tank. C) the continuity between nozzle and hose must be infinity. C) the continuity between nozzle and hose must be infinity. D) there is no fire risk as both
D) there is no fire risk as both the bowser and aircraft are bonded by the bowser and aircraft are bonded by thethe refuelling nozzle.
refuelling nozzle.
An aircraft has three batteries, each
An aircraft has three batteries, each of 12 volts with a of 12 volts with a 40 Ah capacity, connected in series. The40 Ah capacity, connected in series. The resultant unit has:
resultant unit has:
A) a voltage of 36 volts and a capacity of 120 Ah. A) a voltage of 36 volts and a capacity of 120 Ah. B)
B) a voltage of 36 volts and a capacity of 40 Ah. a voltage of 36 volts and a capacity of 40 Ah. C) a voltage of 24 v
C) a voltage of 24 volts and a capacity of 80 Ah.olts and a capacity of 80 Ah. D) a capacity of 120 Ah and a voltage of 12 volts. D) a capacity of 120 Ah and a voltage of 12 volts.
The output voltage of DC generators used in
The output voltage of DC generators used in aircraft is normally regulated by:aircraft is normally regulated by: A)
A) Controlling the current in Controlling the current in the field windingsthe field windings B)
B) Controlling the current in the armature (anker) windingsControlling the current in the armature (anker) windings C)
C) Varying the RPM of the generatorVarying the RPM of the generator
D) Varying the torque applied to the generator D) Varying the torque applied to the generator Which of the
Which of the following statements best describes two resistors connected in parallel?following statements best describes two resistors connected in parallel? A)
A) The combined resistance is always less The combined resistance is always less than the smallest individualthan the smallest individual resistance present.
resistance present. B)
B) Resistors should never be connected in parallel.Resistors should never be connected in parallel. C)
C) The combined resistance is always greater than the largest individualThe combined resistance is always greater than the largest individual resistance present.
resistance present.
D) The combined resistance is equal to
D) The combined resistance is equal to the average of the individualthe average of the individual resistances.
resistances.
What is the purpose of a voltmeter? What is the purpose of a voltmeter?
A) to measure voltage and is fitted in series with the component. A) to measure voltage and is fitted in series with the component.
B) to measure potential difference and is fitted in series with the load. B) to measure potential difference and is fitted in series with the load. C)
C) to measure potential difference and is measured in to measure potential difference and is measured in parallel with theparallel with the component.
component.
D) to measure current. D) to measure current.
When being charged, the specific gravity of the
When being charged, the specific gravity of the electrolyte in a Ni-cad cell:electrolyte in a Ni-cad cell: A) depends on the voltage applied.
A) depends on the voltage applied. B) increases.
B) increases. C)
C) e exhibits little xhibits little change.change. D) decreases.
D) decreases.
A current limiter fuse in a DC generation system is used to: A current limiter fuse in a DC generation system is used to:
A) instantaneously rupture to limit the current in the load A) instantaneously rupture to limit the current in the load B) limit the current in the field circuit
B) limit the current in the field circuit C)
C) allow a short term allow a short term overload before rupturingoverload before rupturing D) limit the current in the armature
D) limit the current in the armature Voltage is proportional to charge on:
Voltage is proportional to charge on: A) an inductance.
A) an inductance. B) a battery.
B) a battery. C)
C) a capacitor. a capacitor. D) a resistor. D) a resistor. 81.
81. DC generators are rated in: DC generators are rated in: A) kVA. A) kVA. B) B) kW. kW. C) kVAR. C) kVAR. D) kWA. D) kWA.
Obvious disadvantages using Lead-Acid batteries in
Obvious disadvantages using Lead-Acid batteries in airplanes are:airplanes are:
A) They are expensive compared to other batteries used in airplanes. A) They are expensive compared to other batteries used in airplanes.
B) They only carry 12 volt, and most modern airplanes use 24 volt circuits. B) They only carry 12 volt, and most modern airplanes use 24 volt circuits. C)
C) They have insufficient capacity and is volume and weight inefficient. They have insufficient capacity and is volume and weight inefficient. D) The Lead-Acid battery is too heavy.
D) The Lead-Acid battery is too heavy.
The purpose of protecting a circuit against excessive current conditions is: The purpose of protecting a circuit against excessive current conditions is: A) to prevent battery run down when a generator has failed A) to prevent battery run down when a generator has failed B)
B) to provide a means of controlling to provide a means of controlling and distributing the current in a circuitand distributing the current in a circuit C)
C) to prevent a reverse to prevent a reverse current causing failure current causing failure of the equipmentof the equipment
D)
D) to prevent deterioration and failure of the aircraft's wiring and switch gear by excess heat.to prevent deterioration and failure of the aircraft's wiring and switch gear by excess heat. An aircraft has 3 navigation lights, each rated at 24 watts, which are connected in parallel and An aircraft has 3 navigation lights, each rated at 24 watts, which are connected in parallel and supplied by a 12 volts battery. What would be the total current that the battery has to deliver to the supplied by a 12 volts battery. What would be the total current that the battery has to deliver to the navigation lights circuit?
navigation lights circuit? A) 1,5 Amperes. A) 1,5 Amperes. B) B) 6 Amperes. 6 Amperes. C) 2 Amperes. C) 2 Amperes. D) 0,5 Amperes. D) 0,5 Amperes. It may be determined that
It may be determined that an aircraft is not an aircraft is not properly bonded if:properly bonded if: A)
A) static noises can static noises can be heard on the be heard on the radio.radio. B)
B) there is interference on the VOR receiver.there is interference on the VOR receiver. C) a circuit breaker pops out.
C) a circuit breaker pops out.
D) there is heavy corrosion on the fuselage
D) there is heavy corrosion on the fuselage skin mountings.skin mountings. When two DC generators are operating in parallel, control of
When two DC generators are operating in parallel, control of load sharing is achieved by:load sharing is achieved by: A)
A) an equalising circuit which, an equalising circuit which, in conjunction with the voltage regulators,in conjunction with the voltage regulators, varies the field excitation current of the generators.
varies the field excitation current of the generators. B)
B) an equalising circuit which, in turn, controls the speed of the generators.an equalising circuit which, in turn, controls the speed of the generators. C) carrying out systematic load-shedding procedures.
C) carrying out systematic load-shedding procedures. D) the synchronous bus-bar.
D) the synchronous bus-bar.
Consider a battery voltage V, connected to four resistors R1, R2, R3, R4.
Consider a battery voltage V, connected to four resistors R1, R2, R3, R4. They are connected as twoThey are connected as two pairs in parallel (R1 and R2, R3 and R4). The two pairs are connected in series: If R1 is twice R2, R3 is pairs in parallel (R1 and R2, R3 and R4). The two pairs are connected in series: If R1 is twice R2, R3 is half R4, and the current in R1 is 9 amps, the current in R4 is:
half R4, and the current in R1 is 9 amps, the current in R4 is: A) 3 amps. A) 3 amps. B) B) 9 amps. 9 amps. C) 18 amps C) 18 amps D) 4.5 amps. D) 4.5 amps.
Two 0.03 Henry inductors are placed in series. The resulting
Two 0.03 Henry inductors are placed in series. The resulting inductance is:inductance is: A) 0,09 H. A) 0,09 H. B) B) 0,06 H. 0,06 H. C) 0,015 H. C) 0,015 H. D) 0,03 H. D) 0,03 H.
An aircraft has a battery with a capacity of 60 Ah. Assuming that it will
An aircraft has a battery with a capacity of 60 Ah. Assuming that it will provide its normal capacity andprovide its normal capacity and is discharged in 10 hours:
is discharged in 10 hours:
A) it will deliver 60 amperes for 10 hours A) it will deliver 60 amperes for 10 hours B)
B) it will deliver 6 it will deliver 6 amperes for 10 hoursamperes for 10 hours C) it w
C) it will deliver 4.8 amperes for 10 hoursill deliver 4.8 amperes for 10 hours D) it will deliver 60 amperes for 1 hour D) it will deliver 60 amperes for 1 hour What efficiency is required in
What efficiency is required in order for a battery to pass a order for a battery to pass a capacity test?capacity test? A) 90% A) 90% B) 60% B) 60% C) 50% C) 50% D) D) 80% 80%
The purpose of bonding is: The purpose of bonding is:
A) to protect against lightning strikes. A) to protect against lightning strikes. B)
B) to keep all parts of the to keep all parts of the aircraft at the same potential.aircraft at the same potential. C) to prevent static electrical charges building
C) to prevent static electrical charges building up.up. D) to keep the aircraft at zero potential.
D) to keep the aircraft at zero potential.
Consider a battery voltage V and two resistors (R1 and R2)
Consider a battery voltage V and two resistors (R1 and R2) which are connected in series: If which are connected in series: If R1 is 2R1 is 2 ohms, R2 has 3 amps through it and 3 volts across it what is V?
ohms, R2 has 3 amps through it and 3 volts across it what is V? A) At most, 3 volts.
A) At most, 3 volts. B) 6 volts.
B) 6 volts.
C) Impossible to tell without knowing R2. C) Impossible to tell without knowing R2. D)
D) 9 volts. 9 volts.
During normal cruise flight conditions a Ni
During normal cruise flight conditions a Ni -Cd battery's ammeter shows a high rate of -Cd battery's ammeter shows a high rate of charge. Whatcharge. What does this indicate?
does this indicate? A)
A) it can be ignored as it it can be ignored as it is quite normalis quite normal B)
B) that the generator should be disconnected from the bus barthat the generator should be disconnected from the bus bar C)
C) that a high demand is being made that a high demand is being made on the systemon the system D)
D) that a possible that a possible thermal runaway existsthermal runaway exists When a centre zero ammeter is reading to the left: When a centre zero ammeter is reading to the left: A)
A) the battery is discharging to the generator.the battery is discharging to the generator. B)
B) the battery is the battery is discharging to the discharging to the system.system. C) the generator is supporting the system. C) the generator is supporting the system. D) no current is flowing.
D) no current is flowing. A circuit breaker:
A circuit breaker: A)
A) may be reset manually after the may be reset manually after the fault has been rectified.fault has been rectified. B)
B) can be reset on the ground only.can be reset on the ground only. C)
C) can only be reset after major maintenance.can only be reset after major maintenance. D) is self resetting after the fault
The voltage of a fully charged lead-acid battery cell is: The voltage of a fully charged lead-acid battery cell is: A) A) 2,2 V 2,2 V B) 1,8 V B) 1,8 V C) 1,4 V C) 1,4 V D) 1,2 V D) 1,2 V
A battery is made up of 5 NiCad cells, each having a voltage of 1.2V and a capacity of 20Ah, A battery is made up of 5 NiCad cells, each having a voltage of 1.2V and a capacity of 20Ah, connected in series. What is
connected in series. What is the resulting combination?the resulting combination? A) 30 V, 100Ah. A) 30 V, 100Ah. B) 12 V, 20Ah. B) 12 V, 20Ah. C) C) 6 V, 20Ah.6 V, 20Ah. D) 6 V, 100Ah. D) 6 V, 100Ah. 1 ampere equals: 1 ampere equals: A) 1,000 microamps A) 1,000 microamps B) B) 1,000 milliamps 1,000 milliamps
C) 1,000,000 millicoulombs per second C) 1,000,000 millicoulombs per second D) 1,000,000 milliamps
D) 1,000,000 milliamps
The advantages of grounding the negative pole of
The advantages of grounding the negative pole of the aircraft structure are:the aircraft structure are: 1.
1. Weight savingWeight saving 2.
2. Easy fault detectionEasy fault detection 3.
3. Increase of short-circuit riskIncrease of short-circuit risk 4.
4. Reduction of short-circuit riskReduction of short-circuit risk 5.
5. Circuits are not single-wired linesCircuits are not single-wired lines
The combination regrouping all the correct statements is : The combination regrouping all the correct statements is : A) 1, 2, 3 A) 1, 2, 3 B) 1, 3, 5 B) 1, 3, 5 C) C) 1, 2, 4 1, 2, 4 D) 2, 3, 5 D) 2, 3, 5
A 12 volt battery is connected to a 24 watt light bulb. The battery lasts for 10 hours. What is the A 12 volt battery is connected to a 24 watt light bulb. The battery lasts for 10 hours. What is the battery capacity? battery capacity? A) 240 Wh. A) 240 Wh. B) 120 Vh. B) 120 Vh. C) 5 Ah. C) 5 Ah. D) D) 20 Ah. 20 Ah. 101.
101.8 volts are applied to a 2 Ohm resistor. What current will flow?8 volts are applied to a 2 Ohm resistor. What current will flow? A) 24 watts. A) 24 watts. B) 4 coulombs. B) 4 coulombs. C) C) 4 amps. 4 amps.
D) 6 coulombs per second. D) 6 coulombs per second.
In a multi
In a multi engined aircraft, how are the ammeters usually arranged?engined aircraft, how are the ammeters usually arranged? A) One for each load bus bar.
A) One for each load bus bar. B) One for all generators. B) One for all generators. C)
C) One for each set One for each set of generators which are of generators which are paralleled.paralleled. D)
D) One for each One for each generator.generator. If you double the EMF, you will: If you double the EMF, you will: A) halve current. A) halve current. B) double power. B) double power. C) double resistance. C) double resistance. D)
D) double current. double current.
When a conductor cuts the flux of a magnetic field: When a conductor cuts the flux of a magnetic field: A)
A) an electromotive force (EMF) an electromotive force (EMF) is induced in is induced in the conductorthe conductor B)
B) current will flow in accordance with Flemings left hand rulecurrent will flow in accordance with Flemings left hand rule C)
C) there will be no effect on the conductorthere will be no effect on the conductor D) the field will collapse
D) the field will collapse Electrical power is expressed in: Electrical power is expressed in: A) Coulombs A) Coulombs B) Amperes B) Amperes C) C) Watts Watts D) Volts D) Volts
A Ni-cad cell is fully charged. Its on load voltage is: A Ni-cad cell is fully charged. Its on load voltage is: A) 2,2 volts. A) 2,2 volts. B) 12 volts. B) 12 volts. C) 24 volts. C) 24 volts. D) D) 1,2 volts. 1,2 volts.
An earth return electrical system has: An earth return electrical system has: A)
A) two leads from each service to the aircraft's structuretwo leads from each service to the aircraft's structure B)
B) one lead to the service and one lone lead to the service and one lead to the structureead to the structure C) two leads from the system to each service
C) two leads from the system to each service D) two leads from the system to the
D) two leads from the system to the structurestructure The capacitance of several capacitors connected in parallel can be
The capacitance of several capacitors connected in parallel can be calculated to be:calculated to be: A) the inverse of the sum of the individual capacitances.
A) the inverse of the sum of the individual capacitances.
B) the inverse of the sum of the inverses of the individual capacitances. B) the inverse of the sum of the inverses of the individual capacitances. C)
C) the sum of the the sum of the individual capacitances.individual capacitances.
D)
D) the sum of the individual capacitances divided by the number of capacitors.the sum of the individual capacitances divided by the number of capacitors.
Parallel wound motors produce a... starting torque and their speed varies... with Parallel wound motors produce a... starting torque and their speed varies... with load.load. A) high, moderately A) high, moderately B) high, slightly B) high, slightly C) low, significantly C) low, significantly D)
The voltage regulator of a DC generator: The voltage regulator of a DC generator:
A) increases voltage when engine RPM increases A) increases voltage when engine RPM increases B)
B) is used to limit generator voltage only when the engine is over speedingis used to limit generator voltage only when the engine is over speeding C)
C) ensures a reverse current flow when the electrical circuit is brokenensures a reverse current flow when the electrical circuit is broken D)
D) maintains a constant maintains a constant voltagevoltage
R1 and R2 resistances are connected in parallel. The
R1 and R2 resistances are connected in parallel. The value of the equivalent resistance (Req) sovalue of the equivalent resistance (Req) so obtained is given by the f
obtained is given by the f ollowing formula:ollowing formula: A) Req = R1 + R2 A) Req = R1 + R2 B) 1/Req = 1/(R1 + R2) B) 1/Req = 1/(R1 + R2) C) Req = R1 x R2 C) Req = R1 x R2 D) D) 1/Req = 1/R1 1/Req = 1/R1 + 1/R2+ 1/R2
In aeronautics, the most commonly used batteries are NiCad
In aeronautics, the most commonly used batteries are NiCad because...because... A)
A) their output voltage is their output voltage is more constant than more constant than lead-acid batterieslead-acid batteries B)
B) their electrolyte is neither corrosive nor dangeroustheir electrolyte is neither corrosive nor dangerous C) they weigh less than lead-acid batteries
C) they weigh less than lead-acid batteries D) they are cheaper than lead-acid batteries D) they are cheaper than lead-acid batteries
The difference in electrical potential between two points in a circuit is measured in: The difference in electrical potential between two points in a circuit is measured in: A) Amperes. A) Amperes. B) Coulombs. B) Coulombs. C) Watts. C) Watts. D) D) Volts. Volts.
Assume a constant speed DC generator providing a constant output voltage. If
Assume a constant speed DC generator providing a constant output voltage. If the electrical loadthe electrical load increases, the voltage regulator will:
increases, the voltage regulator will: A)
A) increase the intensity of increase the intensity of the excitation current.the excitation current. B)
B) maintain the intensity of the excitation current constant.maintain the intensity of the excitation current constant. C)
C) change the direction of the excitation current.change the direction of the excitation current. D) decrease the intensity of the excitation current. D) decrease the intensity of the excitation current. The purpose of an inverter could be:
The purpose of an inverter could be:
A) to supply DC power when the battery is out of service. A) to supply DC power when the battery is out of service. B) to convert AC into DC.
B) to convert AC into DC. C)
C) to provide emergency power to provide emergency power to essential AC to essential AC consumers from a batteryconsumers from a battery bus bar.
bus bar.
D) all answers are correct. D) all answers are correct.
In a circuit containing reactive elements, the total current: In a circuit containing reactive elements, the total current: A)
A) must be out of phase with the voltage.must be out of phase with the voltage. B)
B) may be out of phase with the voltage. may be out of phase with the voltage. C) will be independent of voltage.
C) will be independent of voltage. D) must be in phase with voltage. D) must be in phase with voltage.
An ammeter measures: An ammeter measures: A) Amps per second. A) Amps per second. B) power dissipated. B) power dissipated. C) potential differences. C) potential differences. D)
D) Co Coulombs per ulombs per second.second.
A 12 volt battery has a rating of 24 Ah. If fully charged, how long can it
A 12 volt battery has a rating of 24 Ah. If fully charged, how long can it supply current to a 12 volt, 24supply current to a 12 volt, 24 watt bulb? watt bulb? A) 48 hours. A) 48 hours. B) 6 hours. B) 6 hours. C) C) 12 hours. 12 hours. D) 1 hour. D) 1 hour. Which of the
Which of the following is an appropriate substance to use to following is an appropriate substance to use to neutralise the electrolyte from a Nicadneutralise the electrolyte from a Nicad cell?
cell? A)
A) A dilute solution A dilute solution of boric acid.of boric acid.
B) A concentrated solution of sodium bicarbonate. B) A concentrated solution of sodium bicarbonate. C) Lead sulphate in powdered form.
C) Lead sulphate in powdered form.
D) A dilute solution of sodium bicarbonate. D) A dilute solution of sodium bicarbonate. If one of the 12 cells of a l
If one of the 12 cells of a l ead-acid battery is dead, the battery:ead-acid battery is dead, the battery:
A) has 1/12 less voltage and less capacity, but can still be used. A) has 1/12 less voltage and less capacity, but can still be used. B) has 1/12 less capacity, but can still be used.
B) has 1/12 less capacity, but can still be used. C)
C) is unserviceable. is unserviceable.
D) has 1/12 less voltage, but can still be used. D) has 1/12 less voltage, but can still be used.
121.
121.What is load shedding?What is load shedding?
A) a reduction of the voltage in the system A) a reduction of the voltage in the system B) an increase in the current to services B) an increase in the current to services C)
C) reduction of the total reduction of the total loadsloads
D) distributing of the load between generators D) distributing of the load between generators The voltage regulator of a DC
The voltage regulator of a DC generator is connected in:generator is connected in: A) parallel with the shunt field coil.
A) parallel with the shunt field coil. B)
B) series with the series with the shunt field coil.shunt field coil. C) parallel with the armature. C) parallel with the armature. D) series with the armature. D) series with the armature.
A 12 volt lead acid battery has a broken connection in a cell, the battery: A 12 volt lead acid battery has a broken connection in a cell, the battery: A) will suffer from thermal runaway
A) will suffer from thermal runaway
B) provides 1/12th less voltage for the same time B) provides 1/12th less voltage for the same time C)
C) is unserviceable is unserviceable
D) provides 1/12th less voltage for 1/12th less time D) provides 1/12th less voltage for 1/12th less time
On board present aircraft, the batteries used are-mainly Nickel-Cadmium. Their advantages are: On board present aircraft, the batteries used are-mainly Nickel-Cadmium. Their advantages are:
1.
1. low risk of thermal runawaylow risk of thermal runaway 2.
2. high internal resistance, hence higher powerhigh internal resistance, hence higher power 3.
3. good charging and discharging capability at high ratinggood charging and discharging capability at high rating 4.
4. wider permissible temperature rangewider permissible temperature range 5.
5. good storage capabilitygood storage capability 6.
6. sturdiness owing to its metal casingsturdiness owing to its metal casing 7.
7. the electrolyte density remains the electrolyte density remains unchanged during chargingunchanged during charging The combination of correct statements is:
The combination of correct statements is: A) 2, 3, 4, 5, 6 A) 2, 3, 4, 5, 6 B) B) 3, 4, 5, 3, 4, 5, 66 C) 1, 2, 5, 6, 7 C) 1, 2, 5, 6, 7 D) 3, 4, 6, 7 D) 3, 4, 6, 7
When approaching discharge, the characteristics of a battery are as follows: When approaching discharge, the characteristics of a battery are as follows: A) voltage decreases, internal resistance decreases
A) voltage decreases, internal resistance decreases B)
B) voltage decreases, internal resistance increasvoltage decreases, internal resistance increases, especially with Ni-cadses, especially with Ni-cads C) voltage decreases, internal resistance unchanged
C) voltage decreases, internal resistance unchanged D)
D) voltage decreases, internal resistance voltage decreases, internal resistance increasesincreases The primary purpose of bonding the metallic parts of
The primary purpose of bonding the metallic parts of an aeroplane is to:an aeroplane is to: A) provide a single earth for electrical devices.
A) provide a single earth for electrical devices. B)
B) provide safe distribution of electrical charges and currents. provide safe distribution of electrical charges and currents.
C)
C) isolate all components electrically and thus isolate all components electrically and thus make the static potential make the static potential constant.constant.
D) prevent electrolytic corrosion between mating surfaces of similar
D) prevent electrolytic corrosion between mating surfaces of similar metals.metals. A bus-bar is:
A bus-bar is: A)
A) a device permitting operation of two or more switches together.a device permitting operation of two or more switches together. B)
B) a distribution point a distribution point for electrical power.for electrical power. C) a devic
C) a device which may only be used in DC circuits.e which may only be used in DC circuits. D) the stator of a moving coil instrument.
D) the stator of a moving coil instrument.
The detection of a feeder fault on a direct current circuit results in: The detection of a feeder fault on a direct current circuit results in:
1.
1. automatic disconnection of the generator from the aircraft AC automatic disconnection of the generator from the aircraft AC busbarbusbar 2.
2. opening of generator field current relayopening of generator field current relay 3.
3. opening of the main opening of the main relay of the generator breakerrelay of the generator breaker 4.
4. opening of balancing circuit connecting two generatorsopening of balancing circuit connecting two generators 5.
5. lighting of an indicator lamplighting of an indicator lamp The combination of correct statements is: The combination of correct statements is: A) A) 1, 2, 3, 1, 2, 3, 4, 54, 5 B) 2, 3, 4, 5 B) 2, 3, 4, 5 C) 2, 4, 5 C) 2, 4, 5 D) 1, 3, 5 D) 1, 3, 5
When being charged the specific gravity of the
When being charged the specific gravity of the electrolyte in a lead-acid cell:electrolyte in a lead-acid cell: A)
A) increases. increases.
B) exhibits little change. B) exhibits little change. C) depends on current flow. C) depends on current flow. D) decreases.
A 3 microfarad capacitor is in
A 3 microfarad capacitor is in parallel with a 6 parallel with a 6 microfarad capacitor. What is the combinedmicrofarad capacitor. What is the combined capacitance?
capacitance? A)
A) 9 microfarads 9 microfarads B) 2 microfarads B) 2 microfarads C) 3 microfarads C) 3 microfarads D) 4.5 microfarads D) 4.5 microfarads
12.5 watts are being consumed by a 2
12.5 watts are being consumed by a 2 Ohm resistor. What voltage has been applied?Ohm resistor. What voltage has been applied? A) 6.25 volts.
A) 6.25 volts.
B) Impossible to tell without knowing the current. B) Impossible to tell without knowing the current. C)
C) 5 volts. 5 volts. D) 3.125 volts. D) 3.125 volts. The on-load voltage of a
The on-load voltage of a lead-acid battery is... and is lead-acid battery is... and is measured using...measured using... A) 1.2 Volts, Voltmeter.
A) 1.2 Volts, Voltmeter. B)
B) 2 Volts, Voltmeter. 2 Volts, Voltmeter.
C) 1.35 Volts, battery charger. C) 1.35 Volts, battery charger. D) 2.2 Volts, Capacity meter. D) 2.2 Volts, Capacity meter.
A component that provides 115 VAC output after an i
A component that provides 115 VAC output after an i nput of 28 VDC is nput of 28 VDC is called:called: A) A rotary transformer.
A) A rotary transformer. B)
B) An inverter, static An inverter, static or rotary.or rotary. C) A
C) A transformer / rectifier unit.transformer / rectifier unit. D) A static rectifier.
D) A static rectifier. A 2 Ohm resistor has 3
A 2 Ohm resistor has 3 amps through it. What power is amps through it. What power is being consumed by the resistor?being consumed by the resistor? A) 2 watts
A) 2 watts B)
B) 18 watts 18 watts
C) 18 joules per second C) 18 joules per second D) 4.5 watts
D) 4.5 watts
Resistors in series act as..., resistors in parallel act as... Resistors in series act as..., resistors in parallel act as... A) current subtractors, voltage dividers. A) current subtractors, voltage dividers. B) voltage dividers, voltage subtractors. B) voltage dividers, voltage subtractors. C)
C) voltage dividers, current divvoltage dividers, current dividers.iders. D) current dividers, current subtractors. D) current dividers, current subtractors.
Consider a battery voltage V, connected to three resistors R1, R2, R3. R2
Consider a battery voltage V, connected to three resistors R1, R2, R3. R2 and R3 are in parallel and R3 are in parallel withwith one another, and the combination of them is in series with R1. If R1 is 3 Ohms, R2 is
one another, and the combination of them is in series with R1. If R1 is 3 Ohms, R2 is 10 Ohms and R310 Ohms and R3 is 5 Ohms, what is the total resistance of the circuit?
is 5 Ohms, what is the total resistance of the circuit? A) 18 Ohms. A) 18 Ohms. B) 1.58 Ohms. B) 1.58 Ohms. C) C) 6.33 Ohms. 6.33 Ohms. D) 7.31 Ohms. D) 7.31 Ohms.
In an electrical circuit
In an electrical circuit with 28V, 7A and 4ohms, the dissipated power is with 28V, 7A and 4ohms, the dissipated power is equal to:equal to: A) 28 Watts A) 28 Watts B) 113 Watts B) 113 Watts C) 196 Volts C) 196 Volts D) D) 196 Watts 196 Watts
If the frequency of the supply in a series capacitive circuit is increased, the current flowing in the If the frequency of the supply in a series capacitive circuit is increased, the current flowing in the circuit will:
circuit will: A) decrease. A) decrease.
B) remain the same. B) remain the same. C)
C) increase. increase. D) be zero. D) be zero.
Overloading an electrical circuit causes the fuse to
Overloading an electrical circuit causes the fuse to blow. This:blow. This: A) fractures the fuse case.
A) fractures the fuse case.
B) disconnects the fuse from its holder. B) disconnects the fuse from its holder. C)
C) melts the fuse linmelts the fuse link wire.k wire.
D) bends the bimetallic strip out of position. D) bends the bimetallic strip out of position. One essential law of magnetism is:
One essential law of magnetism is:
A) Equal poles attracts each other and unequal poles repel each other. A) Equal poles attracts each other and unequal poles repel each other. B) Magnetic power equals the product of current and voltage.
B) Magnetic power equals the product of current and voltage. C)
C) A permanent magnet bar will always have a north and a south pole. A permanent magnet bar will always have a north and a south pole. D) The distance between the poles does not affect the amount of attraction D) The distance between the poles does not affect the amount of attraction
between poles. between poles. 141.
141.There is a maximum amount There is a maximum amount of flux which can of flux which can be carried by a piece of be carried by a piece of ferromagnetic material.ferromagnetic material.
This is due to: This is due to:
A) energy loss due to hysteresis A) energy loss due to hysteresis B) B) saturation saturation C) residual magnetism C) residual magnetism D) high coercivity D) high coercivity
Electrical services are connected in parallel. When some are switched off: Electrical services are connected in parallel. When some are switched off:
A) current may increase or decrease, depending on battery internal A) current may increase or decrease, depending on battery internal
resistance resistance
B) current increases B) current increases C)
C) current decreases current decreases
D) current stays the same D) current stays the same
Voltage is expressed in... and the basic SI units for it are... Voltage is expressed in... and the basic SI units for it are... A) Tension, C/J A) Tension, C/J B) Volteres, C/J B) Volteres, C/J C) Emf, J/C C) Emf, J/C D) D) Volts, J/C Volts, J/C
Switching a DC alternator off i
Switching a DC alternator off i s achieved by:s achieved by: A) Open circuiting the armature. A) Open circuiting the armature. B)
B) Open circuiting the Open circuiting the field electromagnet.field electromagnet. C) Close circuiting the electromagnet.
C) Close circuiting the electromagnet. D) Close circuiting the armature.
D) Close circuiting the armature. The SI unit used for measuring... is... The SI unit used for measuring... is... A)
A) resistance, Ohms. resistance, Ohms. B) EMF, Amperes. B) EMF, Amperes. C) current, Volts. C) current, Volts. D) energy, Watts. D) energy, Watts.
What type of electrical circuit i
What type of electrical circuit i s usually protected using a current limiter?s usually protected using a current limiter? A)
A) High duty power dHigh duty power distribution circuitsistribution circuits B) DC circuits only
B) DC circuits only
C) Low duty power distribution circuits C) Low duty power distribution circuits D) Logic circuits
D) Logic circuits
Consider a battery voltage V, connected to three resistors R1, R2, R3. R2 and
Consider a battery voltage V, connected to three resistors R1, R2, R3. R2 and R3 are in parallel withR3 are in parallel with one another, and the combination of them is in series with R1. If R2 is twice R3 and has 2 amps one another, and the combination of them is in series with R1. If R2 is twice R3 and has 2 amps running through it, the
running through it, the power consumed by R3 is 16 watts, V is power consumed by R3 is 16 watts, V is 12 volts, what is the 12 volts, what is the power consumedpower consumed by R1? by R1? A) 24 watts. A) 24 watts. B) B) 48 watts. 48 watts. C) Impossib
C) Impossible to tell without knowing either R1 or R2.le to tell without knowing either R1 or R2. D) 72 watts.
D) 72 watts.
What is the purpose of an ammeter? What is the purpose of an ammeter? A)
A) to measure emf when fitted in series with the componentto measure emf when fitted in series with the component B)
B) to measure current when fitted in series in to measure current when fitted in series in the circuitthe circuit C) to measure current when fitted in parallel in the circuit C) to measure current when fitted in parallel in the circuit D) to measure resistance
D) to measure resistance If a DC circuit with a total
If a DC circuit with a total resistance of 2 Ohms has 12 volts DC applied, then the resulting current is:resistance of 2 Ohms has 12 volts DC applied, then the resulting current is: A) 10 A. A) 10 A. B) 24 A. B) 24 A. C) C) 6 A. 6 A. D) 0,167 A. D) 0,167 A.
Consider a battery voltage V, connected to R1 and R2 which are in parallel: If V is 12 volts and R1 is 4 Consider a battery voltage V, connected to R1 and R2 which are in parallel: If V is 12 volts and R1 is 4 Ohms, what current is flowing t
Ohms, what current is flowing t hrough R2?hrough R2? A) 3 amps.
A) 3 amps.
B) Impossible to tell, but must be at most 3 amps. B) Impossible to tell, but must be at most 3 amps. C)
C) Impossible to tell wImpossible to tell without further information.ithout further information. D) Impossible to tell, but must be at least 3
Alternating current (AC):
Alternating current (AC):
When AC generators are operated in parallel, they must
When AC generators are operated in parallel, they must be of the same:be of the same: A) frequency and amperage.
A) frequency and amperage. B)
B) voltage and frequency. voltage and frequency. C) amperage and kVAR. C) amperage and kVAR. D) voltage and amperage. D) voltage and amperage. The oil system of an IDG will be: The oil system of an IDG will be: A)
A) the same as the main hydraulic the same as the main hydraulic aircraft system.aircraft system. B)
B) drawn from a common resedrawn from a common reservoir shared by all engines and IDG's.rvoir shared by all engines and IDG's. C)
C) drawn from a common resedrawn from a common reservoir shared by all IDG's.rvoir shared by all IDG's. D)
D) independent of all other IDG's and independent of the independent of all other IDG's and independent of the hydraulic system.hydraulic system. Typical aircraft AC system run on:
Typical aircraft AC system run on: A) 50 Hz, 115 volts. A) 50 Hz, 115 volts. B) 400 Hz, 250 volts. B) 400 Hz, 250 volts. C) 50 Hz, 24 volts. C) 50 Hz, 24 volts. D) D) 400 Hz, 115 400 Hz, 115 volts.volts.
A unit that converts electrical DC into AC is: A unit that converts electrical DC into AC is: A) an AC generator
A) an AC generator B)
B) an inverter an inverter C) a thermistor C) a thermistor
D) a transformer rectifier unit D) a transformer rectifier unit When loaded, an induction motor: When loaded, an induction motor: A)
A) can run at any speed, depending can run at any speed, depending upon the applied load.upon the applied load. B)
B) can run at any speed, depending can run at any speed, depending on the applied voltage.on the applied voltage. C) runs at exactly synchronous speed.
C) runs at exactly synchronous speed. D)
D) runs at less tharuns at less than synchronous speed.n synchronous speed. Which of this
Which of this circuit diagram symbols represents ancircuit diagram symbols represents an auto-transformer? auto-transformer? A) A. A) A. B) B) C.C. C) D. C) D. D) B. D) B.
