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SVP Auto Electrician study materials
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SVP Auto Electrician practice questions

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Question 1Occupational safety, hand tools, test equipment and workshop practice

Which fire extinguisher is the correct choice for a fire at a live electrical test bench?

  1. Wet chemical
  2. Foam
  3. Carbon dioxide (CO2) Correct answer.
  4. Water under pressure

Explanation

CO2 is non-conductive and leaves no residue, so it can be discharged onto energised equipment without creating a shock path. Water-based media conduct electricity and would spread the fire and damage equipment.

Question 2Occupational safety, hand tools, test equipment and workshop practice

Battery electrolyte splashes onto your forearm. What is the correct immediate action?

  1. Flush with plenty of clean water Correct answer.
  2. Wait and see whether a burn develops
  3. Rub the area dry with a rag
  4. Apply a thick layer of grease

Explanation

Electrolyte is dilute sulfuric acid, so the priority is to dilute and wash it away with copious clean water, then seek medical advice. Rubbing the skin drives acid deeper into tissue and delays treatment.

Question 3Occupational safety, hand tools, test equipment and workshop practice

Which practice is correct when lifting a heavy battery from a bench?

  1. Keep the legs straight and bend at the waist
  2. Hold the battery out at arm's length
  3. Bend the knees and keep the load close Correct answer.
  4. Twist the torso as the load comes up

Explanation

Bending the knees and holding the load close to the body keeps the spine upright and shortens the lever arm, greatly reducing stress on the lower back. Straight legs and twisting both load the discs in a way that commonly causes injury.

Question 4Occupational safety, hand tools, test equipment and workshop practice

A technician uses a flat-blade screwdriver as a chisel to split a seized connector. Why is this unsafe?

  1. The blade may shatter and send fragments flying Correct answer.
  2. The screwdriver will not fit the connector
  3. The screwdriver will lose its chrome finish
  4. The handle will damage the connector

Explanation

Screwdrivers are hardened for turning, not for impact, so the tip can chip and throw sharp fragments. Impact work needs a purpose-made chisel or punch plus eye protection.

Question 5Occupational safety, hand tools, test equipment and workshop practice

A hydrometer reading of 1.265 taken at 25 °C on a lead-acid battery indicates which state of charge?

  1. Overcharged with excess acid
  2. Almost completely flat
  3. About half discharged
  4. Fully charged Correct answer.

Explanation

A healthy, fully charged cell reads roughly 1.265 specific gravity at 25 °C, falling to around 1.200 at half charge and near 1.120 when flat. Readings taken away from 25 °C need a temperature correction.

Question 6Occupational safety, hand tools, test equipment and workshop practice

Which eye protection is appropriate when using a compressed-air blow gun to clean a component?

  1. Ordinary reading glasses
  2. Goggles with side protection Correct answer.
  3. A welding helmet
  4. A dust mask worn on its own

Explanation

Compressed air can lift particles and fluid at high speed from any direction, so sealed goggles with side protection are needed. Spectacles leave a gap at the side and a dust mask protects the airway only.

Question 7Occupational safety, hand tools, test equipment and workshop practice

When removing a battery from a vehicle with a negative earth system, which terminal should be disconnected first?

  1. Negative, since it is earthed to the body Correct answer.
  2. Positive, because it carries the full current
  3. Positive, since it is protected by a fuse
  4. Either terminal, since order makes no difference

Explanation

With the negative post earthed, disconnecting it first means a slipped spanner cannot bridge from the positive post to the body and cause a short. The negative is reconnected last for the same reason.

Question 8Occupational safety, hand tools, test equipment and workshop practice

How should a click-type torque wrench be stored after use?

  1. With the scale set to its highest value
  2. Locked in its case at the last used setting
  3. With the drive square immersed in oil
  4. Wound back to its lowest setting Correct answer.

Explanation

Storing a spring-type wrench at a high setting keeps the spring compressed and causes the calibration to drift. It should be wound down to the lowest marked setting and kept clean and dry.

Question 9Occupational safety, hand tools, test equipment and workshop practice

To measure the current flowing through a fuel pump circuit with a digital multimeter, how must the meter be connected?

  1. In parallel across the pump
  2. Across the battery posts
  3. Between the pump body and earth
  4. In series with the circuit Correct answer.

Explanation

Current must pass through the meter, so the ammeter is inserted in series with the load. Its very low internal resistance would cause a massive short if it were connected in parallel.

Question 10Occupational safety, hand tools, test equipment and workshop practice

Which condition must be met when using a clamp meter to read alternator output current?

  1. The meter must first be set to the volts range
  2. The clamp jaws must be left partly open
  3. The clamp must enclose one conductor only Correct answer.
  4. The clamp must enclose both the charge and earth cables

Explanation

A clamp meter measures the magnetic field around a conductor, so it must surround a single cable with the jaws fully closed. Enclosing both the supply and return makes the fields cancel and the reading falls to near zero.

Question 11Occupational safety, hand tools, test equipment and workshop practice

When jump starting a vehicle with a flat battery, where should the final negative connection be made?

  1. To the alternator output terminal
  2. To the positive post of the good battery
  3. To the negative post of the flat battery
  4. To an engine earth away from the battery Correct answer.

Explanation

The last connection is made to a clean metal point away from the battery so that any spark occurs where vented hydrogen cannot collect. Connecting directly at the flat battery risks igniting gas around the case.

Question 12Occupational safety, hand tools, test equipment and workshop practice

A cable of 2.5 mm² cross-section feeds a circuit. How should the correct fuse rating be chosen?

  1. At twice the current the load draws
  2. At the highest rating that fits the holder
  3. At the current marked on the alternator
  4. Below the cable's current-carrying capacity Correct answer.

Explanation

The fuse protects the wiring, so its rating must not exceed the cable's continuous current rating while still sitting above normal load current. A larger fuse lets the cable overheat and burn before the fuse operates.

Question 13Occupational safety, hand tools, test equipment and workshop practice

How should a spill of battery electrolyte on the workshop floor be dealt with?

  1. Wash it into the drain with water
  2. Cover it with a layer of engine oil
  3. Neutralise with soda ash, then rinse Correct answer.
  4. Mop it up with a dry paper towel

Explanation

Acid is best neutralised with an alkaline agent such as soda ash or sodium bicarbonate before the residue is rinsed away. Wearing PPE and ventilating the area are part of the same procedure.

Question 14Occupational safety, hand tools, test equipment and workshop practice

What is the purpose of clipping a heat shunt to a component lead while soldering?

  1. To hold the wire in alignment
  2. To speed up the melting of solder
  3. To earth the component against static
  4. To carry heat away from the component Correct answer.

Explanation

A small metal clip conducts heat away from the joint so the component body stays below its temperature limit. It does not change how quickly the solder flows.

Question 15Occupational safety, hand tools, test equipment and workshop practice

Why must a lead-acid battery be charged in a well-ventilated area?

  1. Because charging gives off explosive hydrogen Correct answer.
  2. To keep the electrolyte from freezing
  3. To stop the charger from overheating
  4. Because oxygen is consumed during charging

Explanation

Gassing at the end of charge releases hydrogen and oxygen, and a hydrogen-in-air mixture above about 4 percent is explosive. Ventilation keeps the concentration below that level and removes ignition sources.

Question 16Occupational safety, hand tools, test equipment and workshop practice

A test lamp is used to probe a sensor signal wire on a modern vehicle. Why is a high-impedance digital multimeter the better choice?

  1. It does not need a good earth connection
  2. It draws almost no current from the circuit Correct answer.
  3. It measures current without breaking the circuit
  4. It takes readings faster than a test lamp

Explanation

A filament lamp draws enough current to load or damage low-power electronic circuits and gives only a rough yes/no indication. A high-impedance meter of 10 MΩ or more barely loads the circuit and shows the true voltage.

Question 17Occupational safety, hand tools, test equipment and workshop practice

Before insulation resistance testing a vehicle circuit with a megohmmeter, which action is essential?

  1. Set the meter to the volts range
  2. Run the engine at fast idle
  3. Top up the battery with distilled water
  4. Disconnect the electronic control units Correct answer.

Explanation

An insulation tester applies a high test voltage, typically 250 to 1000 V, which will destroy semiconductors and control units, so they must be isolated and the circuit de-energised first. The instrument must also be set to its insulation range.

Question 18Occupational safety, hand tools, test equipment and workshop practice

What is the correct approach to the orange high-voltage cables on a hybrid or electric vehicle?

  1. Treat them as live until proven isolated Correct answer.
  2. Discharge them by shorting to the chassis
  3. Probe them with a standard test lamp
  4. Cut and insulate them before bodywork

Explanation

High-voltage cables are live whenever the traction battery is connected, so they are treated as live until a trained person follows the manufacturer's isolation procedure and verifies dead with a suitably rated meter. A discharge wait time is then observed.

Question 19Occupational safety, hand tools, test equipment and workshop practice

Why does a CAT III 1000 V rating matter on a multimeter and its test leads?

  1. It guarantees the reading accuracy is 0.1 %
  2. It allows the meter to measure up to 1000 A
  3. It makes the leads suitable for insulation testing
  4. It certifies transient overvoltage withstand Correct answer.

Explanation

CAT ratings describe how much transient overvoltage an instrument can safely withstand in a given location, with CAT III covering distribution circuits inside a building. Accuracy and current range are entirely separate specifications.

Question 20Occupational safety, hand tools, test equipment and workshop practice

A colleague is gripping a live 230 V conductor and cannot let go. What should you do first?

  1. Hand them a metal bar to grip
  2. Pour water over the conductor
  3. Isolate the supply at the breaker Correct answer.
  4. Pull them clear by the arm

Explanation

The supply must be isolated before the casualty is touched, otherwise the rescuer becomes a second victim of the same fault. Only if isolation is impossible should insulated material be used to separate the person from the conductor.

Question 21Electrical and electronic fundamentals (Ohm's law, series/parallel circuits, magnetism, semiconductors)

A 12 V battery is connected across a 4 Ω resistor. What current flows through the resistor?

  1. 0.33 A
  2. 16 A
  3. 3 A Correct answer.
  4. 48 A

Explanation

Ohm's law states that current equals voltage divided by resistance. Dividing 12 V by 4 Ω gives 3 A. The resistance limits the current to that value for the applied voltage.

Question 22Electrical and electronic fundamentals (Ohm's law, series/parallel circuits, magnetism, semiconductors)

In a series circuit containing two different resistors, how does the current through the second resistor compare with the current through the first?

  1. It equals the total voltage
  2. It is twice as large
  3. It is half as large
  4. It is the same Correct answer.

Explanation

A series circuit provides only one path for charge, so the same current passes through every component in turn. Resistance values affect the voltage drops, not the current at different points in the loop.

Question 23Electrical and electronic fundamentals (Ohm's law, series/parallel circuits, magnetism, semiconductors)

Two identical resistors are connected in parallel directly across a battery. What is the voltage across each resistor?

  1. Twice the source voltage
  2. Half the source voltage
  3. Equal to the source voltage Correct answer.
  4. Divided by the number of branches

Explanation

Parallel branches are connected across the same two nodes, so each branch sees the full source voltage. Adding more branches increases total current but does not reduce the voltage per branch.

Question 24Electrical and electronic fundamentals (Ohm's law, series/parallel circuits, magnetism, semiconductors)

Which rule gives the direction of the magnetic field around a straight current-carrying conductor?

  1. Lenz's law
  2. Faraday's law
  3. Fleming's left-hand rule
  4. The right-hand grip rule Correct answer.

Explanation

Pointing the right thumb along the conventional current, the curled fingers show the field direction circling the conductor. This is the right-hand grip rule. The other rules deal with force or induced EMF.

Question 25Electrical and electronic fundamentals (Ohm's law, series/parallel circuits, magnetism, semiconductors)

A silicon diode starts to conduct appreciable forward current when the forward voltage reaches approximately which value?

  1. 0.7 V Correct answer.
  2. 3.0 V
  3. 1.4 V
  4. 0.2 V

Explanation

The barrier potential of a silicon PN junction is about 0.7 V at normal temperatures. Below this knee voltage the diode conducts only a negligible leakage current.

Question 26Electrical and electronic fundamentals (Ohm's law, series/parallel circuits, magnetism, semiconductors)

A 24 V supply drives a current of 2 A through a resistor. What is the resistance?

  1. 0.083 Ω
  2. 26 Ω
  3. 12 Ω Correct answer.
  4. 48 Ω

Explanation

Rearranging Ohm's law gives resistance equal to voltage divided by current. Dividing 24 V by 2 A gives 12 Ω.

Question 27Electrical and electronic fundamentals (Ohm's law, series/parallel circuits, magnetism, semiconductors)

Two 12 Ω resistors are connected in parallel. What is the equivalent resistance of the combination?

  1. 3 Ω
  2. 12 Ω
  3. 24 Ω
  4. 6 Ω Correct answer.

Explanation

For two equal resistors in parallel the equivalent is half of one value, since 1/R = 1/12 + 1/12 = 1/6. The result, 6 Ω, is lower than either individual resistor, as always with parallel paths.

Question 28Electrical and electronic fundamentals (Ohm's law, series/parallel circuits, magnetism, semiconductors)

A 12 V supply feeds a 4 Ω resistor and an 8 Ω resistor in series. What is the voltage across the 8 Ω resistor?

  1. 4 V
  2. 6 V
  3. 12 V
  4. 8 V Correct answer.

Explanation

The total resistance is 12 Ω, so the current is 1 A. That current through 8 Ω produces a drop of 8 V, leaving 4 V across the other resistor.

Question 29Electrical and electronic fundamentals (Ohm's law, series/parallel circuits, magnetism, semiconductors)

According to Lenz's law, the direction of an induced EMF is always such that it does what?

  1. Follows the clockwise direction in any loop
  2. Aids the change that produced it
  3. Depends only on the loop resistance
  4. Opposes the change that produced it Correct answer.

Explanation

Lenz's law expresses conservation of energy: the induced effect counteracts the change in flux that created it. If it aided the change, energy would be produced without an external source.

Question 30Electrical and electronic fundamentals (Ohm's law, series/parallel circuits, magnetism, semiconductors)

In an N-type semiconductor material, which charge carriers are the majority?

  1. Electrons are the majority carriers Correct answer.
  2. Holes are the majority carriers
  3. The material carries a net electric charge
  4. No free charge carriers are present

Explanation

N-type material is doped with donor atoms that contribute extra conduction electrons, making electrons the majority carriers. Holes exist only as the minority carriers.

Question 31Electrical and electronic fundamentals (Ohm's law, series/parallel circuits, magnetism, semiconductors)

What is the normal purpose of a Zener diode in a power supply circuit?

  1. Voltage regulation in reverse breakdown Correct answer.
  2. Emitting light when forward biased
  3. Rectifying an alternating current supply
  4. Amplifying small signal voltages

Explanation

A Zener diode is operated in reverse breakdown, where its voltage stays nearly constant over a wide current range. This makes it useful as a shunt voltage reference or regulator.

Question 32Electrical and electronic fundamentals (Ohm's law, series/parallel circuits, magnetism, semiconductors)

An electromagnet coil is rewound with twice as many turns while the same current flows. What happens to the magnetic field strength?

  1. It becomes one quarter
  2. It approximately doubles Correct answer.
  3. It halves
  4. It stays the same

Explanation

Field strength in a coil depends on ampere-turns, the product of current and number of turns. Doubling the turns at constant current doubles that product, so the field roughly doubles.

Question 33Electrical and electronic fundamentals (Ohm's law, series/parallel circuits, magnetism, semiconductors)

A 12 V supply feeds a 6 Ω resistor in series with a parallel pair of two 6 Ω resistors. What total current flows from the supply?

  1. 1.33 A Correct answer.
  2. 2 A
  3. 3 A
  4. 0.75 A

Explanation

The parallel pair is 6/2 = 3 Ω, which adds to the series 6 Ω for a total of 9 Ω. Dividing 12 V by 9 Ω gives about 1.33 A.

Question 34Electrical and electronic fundamentals (Ohm's law, series/parallel circuits, magnetism, semiconductors)

A battery of EMF 12 V has an internal resistance of 0.5 Ω and delivers 4 A. What is the terminal voltage?

  1. 10 V Correct answer.
  2. 8 V
  3. 14 V
  4. 12 V

Explanation

The internal resistance causes an internal drop equal to current times internal resistance, 4 A × 0.5 Ω = 2 V. Subtracting this from the EMF leaves a terminal voltage of 10 V.

Question 35Electrical and electronic fundamentals (Ohm's law, series/parallel circuits, magnetism, semiconductors)

A 10 Ω and a 5 Ω resistor are connected in series across a battery. Which one dissipates more power, and why?

  1. The 5 Ω resistor, since current favours the lower resistance
  2. The 10 Ω resistor, because P = I²R Correct answer.
  3. They dissipate equal power because the current is equal
  4. Power cannot be compared without knowing the supply voltage

Explanation

Resistors in series carry the same current, so power is set by I²R and grows with resistance. The 10 Ω resistor therefore dissipates twice the power of the 5 Ω resistor.

Question 36Electrical and electronic fundamentals (Ohm's law, series/parallel circuits, magnetism, semiconductors)

How many diodes in a bridge rectifier conduct during each half cycle of the AC input?

  1. All four
  2. Two Correct answer.
  3. Three
  4. One

Explanation

A bridge rectifier steers each half cycle through one opposite pair of diodes, so two conduct at a time. The other pair is reverse biased and blocks.

Question 37Electrical and electronic fundamentals (Ohm's law, series/parallel circuits, magnetism, semiconductors)

Which statement about resistors connected in parallel is always true?

  1. The current through each resistor is always equal
  2. The total resistance equals the sum of the values
  3. The total resistance is less than the smallest resistor Correct answer.
  4. The total resistance is greater than the largest resistor

Explanation

Each extra parallel path gives charge another route, so the overall resistance must fall below the smallest individual value. Currents divide between branches according to their resistances.

Question 38Electrical and electronic fundamentals (Ohm's law, series/parallel circuits, magnetism, semiconductors)

A resistor is connected to a fixed voltage supply, and its resistance is then doubled. What happens to the current?

  1. It quadruples
  2. It doubles
  3. It halves Correct answer.
  4. It stays the same

Explanation

With voltage held constant, Ohm's law makes current inversely proportional to resistance. Doubling the resistance therefore halves the current.

Question 39Electrical and electronic fundamentals (Ohm's law, series/parallel circuits, magnetism, semiconductors)

Which unit is used to express magnetic flux density?

  1. Weber
  2. Tesla Correct answer.
  3. Farad
  4. Henry

Explanation

Magnetic flux density, the field strength per unit area, is measured in tesla. The weber measures flux itself, which is flux density multiplied by area.

Question 40Electrical and electronic fundamentals (Ohm's law, series/parallel circuits, magnetism, semiconductors)

How does the resistance of a pure semiconductor change as its temperature rises?

  1. It falls as temperature rises Correct answer.
  2. It rises steadily with temperature
  3. It stays the same at all temperatures
  4. It drops instantly to zero

Explanation

Heat breaks additional covalent bonds, releasing more electron-hole pairs that carry current. The increased carrier concentration lowers the resistance, giving a negative temperature coefficient.

Question 41Electrical and electronic fundamentals (Ohm's law, series/parallel circuits, magnetism, semiconductors)

Which unit is used to measure electrical resistance?

  1. Watt
  2. Ohm Correct answer.
  3. Ampere
  4. Volt

Explanation

Resistance is measured in ohms, the ratio of volts to amperes. The other units describe potential difference, current and power respectively.

Question 42Electrical and electronic fundamentals (Ohm's law, series/parallel circuits, magnetism, semiconductors)

Two 10 Ω resistors are connected in series. What is their combined resistance?

  1. 5 Ω
  2. 10 Ω
  3. 20 Ω Correct answer.
  4. 100 Ω

Explanation

Series resistances add directly, so 10 Ω plus 10 Ω gives 20 Ω. The same current must pass through both, and each contributes its own opposition.

Question 43Electrical and electronic fundamentals (Ohm's law, series/parallel circuits, magnetism, semiconductors)

What happens when the like poles of two permanent magnets are brought close together?

  1. They attract each other
  2. They cancel each other out
  3. They repel each other Correct answer.
  4. They become electrically neutral

Explanation

Like magnetic poles repel and unlike poles attract. The repulsion arises from the interaction of their external fields, which oppose each other between the facing poles.

Question 44Electrical and electronic fundamentals (Ohm's law, series/parallel circuits, magnetism, semiconductors)

An NPN transistor is driven fully into saturation while acting as a switch. The collector-emitter voltage is closest to which value?

  1. 0.2 V Correct answer.
  2. 12 V
  3. 0.7 V
  4. 6 V

Explanation

In saturation the transistor behaves almost like a closed switch, so its collector-emitter voltage falls to a few tenths of a volt. The 0.7 V figure applies to the base-emitter junction instead.

Question 45Electrical and electronic fundamentals (Ohm's law, series/parallel circuits, magnetism, semiconductors)

Two wires supply a junction with 3 A and 2 A respectively. What current leaves the junction through the single outgoing wire?

  1. 6 A
  2. 5 A Correct answer.
  3. 2.5 A
  4. 1 A

Explanation

Kirchhoff's current law requires charge to be conserved at a junction, so the total current in equals the total current out. Adding 3 A and 2 A gives 5 A leaving.

Question 46Electrical and electronic fundamentals (Ohm's law, series/parallel circuits, magnetism, semiconductors)

Which unit is used to express capacitance?

  1. Farad Correct answer.
  2. Tesla
  3. Weber
  4. Henry

Explanation

Capacitance is the ability to store charge per unit of applied voltage, so one farad equals one coulomb per volt. The farad is the SI derived unit for this quantity.

Question 47Electrical and electronic fundamentals (Ohm's law, series/parallel circuits, magnetism, semiconductors)

A 24 V electric motor draws a current of 5 A while running. What electrical power does it consume?

  1. 29 W
  2. 120 W Correct answer.
  3. 4.8 W
  4. 600 W

Explanation

Electrical power in a DC circuit equals voltage multiplied by current, so 24 V × 5 A gives 120 W. This is the rate at which the motor takes energy from the supply.

Question 48Electrical and electronic fundamentals (Ohm's law, series/parallel circuits, magnetism, semiconductors)

A transformer has 1200 turns on its primary winding, which is connected to a 240 V AC supply. Its secondary winding has 100 turns. What is the secondary voltage?

  1. 2 V
  2. 2880 V
  3. 24 V
  4. 20 V Correct answer.

Explanation

For an ideal transformer the voltage ratio equals the turns ratio: secondary voltage equals primary voltage multiplied by secondary turns divided by primary turns. Here 240 V × (100 / 1200) gives 20 V.

Question 49Electrical and electronic fundamentals (Ohm's law, series/parallel circuits, magnetism, semiconductors)

A silicon diode with a forward voltage drop of 0.7 V is connected in series with a 470 Ω resistor across a 12 V DC supply. What current flows in the circuit?

  1. 12 mA
  2. 11 mA
  3. 24 mA Correct answer.
  4. 26 mA

Explanation

The diode drop subtracts from the supply, leaving 11.3 V across the resistor. Applying Ohm's law, 11.3 V ÷ 470 Ω gives about 0.024 A, or 24 mA.

Question 50Electrical and electronic fundamentals (Ohm's law, series/parallel circuits, magnetism, semiconductors)

The current through a 0.2 H inductor is changing at a rate of 50 A per second. What is the magnitude of the EMF induced in the inductor?

  1. 0.004 V
  2. 2.5 V
  3. 250 V
  4. 10 V Correct answer.

Explanation

Self-induced EMF equals inductance multiplied by the rate of change of current, e = L × (di/dt). With 0.2 H and 50 A/s the induced EMF is 10 V, opposing the change that produced it.