Question 1
(1 point)
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What is the force that breaks the welding arc? (Multiple Choice)
Question 1 options:
A) Impedance
B) Inductance
C) Magnetic field
D) Electrical potential
Question 2 (1 point)
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SAW requires an additional component when it is used with constant
current. What is that component? (Multiple Choice)
Question 2 options:
A) Arc ignition
B) Arc stabilizer
C) Arc force
D) Voltage sensing wire feeder
Question 3 (1 point)
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A plasma can best be described as: (Multiple Choice)
Question 3 options:
A) an ionized gas.
B) an inert gas.
C) a good insulator.
D) a high temperature gas.
Question 4 (1 point)
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If the total length of a cable is 18 metres, which cable according to
AWG (American Wire Gauge) would give you better conductivity?
(Multiple Choice)
Question 4 options:
A) 4
B) 2
C) 1
D) 1/0
Question 5 (1 point)
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To create or support an ionizing path in arc starting circuits for a high
frequency setting, the ratio of volts to amps is: (Multiple Choice)
Question 5 options:
A) 2 volts with 0.005 amps
B) 50 volts with 30 amps
C) 20,000 volts with 0.005 amps
D) None of the above
Question 6 (1 point)
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Select the correct statement. (Multiple Choice)
Question 6 options:
A) A CC welding power source can be used for the GTAW and PAW processes.
B) A CC welding power source can be used for the SMAW process.
C) A CV welding power source can be used for the GMAW and FCAW processes.
D) All of the above.
Question 7 (1 point)
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A method of GTAW arc starting that uses a low voltage and current to
preheat the electrode is called: (Multiple Choice)
Question 7 options:
A) high frequency starting.
B) impulse starting.
C) scratch starting.
D) lift starting.
Question 8 (1 point)
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GTAW and PAW power sources are commonly designed with high
frequency units. What does the high frequency unit do? (Multiple
Choice)
Question 8 options:
A) Increases heat input due to the increased frequency
B) Outputs high voltage, low current to breakdown the gases in the gap between electrodes, creating a
stable conductive path for the flow of power
C) Decreases the cleaning action created by electrode negative polarity in AC arcs
D) Balances current flow between electrode positive and electrode negative
Question 9 (1 point)
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What type of power source uses a voltage-sensing wire feed system to
produce a stable self-regulating welding arc? (Multiple Choice)
Question 9 options:
A) CC power source
B) CV power source
C) CV inverter power source
D) CV power source with above-average droop
Question 10 (1 point)
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Metals are considered good conductors because: (Multiple Choice)
Question 10 options:
A) their electrons are tightly held by the nucleus.
B) they have many free neutrons.
C) they have many free electrons.
D) they have many free protons.
Question 11 (1 point)
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Inverter welding power sources are typically used for the pulsed
GMAW process because: (Multiple Choice)
Question 11 options:
A) the output can be changed in less than 1/40,000 of a second.
B) a feedback system is not used.
C) the static characteristics cannot be changed.
D) the current output is not limited.
Question 12 (1 point)
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What is the minimum temperature in the centre of a welding arc
column? (Multiple Choice)
Question 12 options:
A) 500 °C
B) 1,000 °C
C) 5,000 °C
D) 50,000 °C
Question 13 (1 point)
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The severity of an electric shock depends principally on: (Multiple
Choice)
Question 13 options:
A) magnitude of the current and body size
B) magnitude of the current and part of the body through which it passes
C) only on the level of humidity in the environment
D) the amount of current only
Question 14 (1 point)
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Early DC generators relied on ____________to produce welding power.
(Multiple Choice)
Question 14 options:
A) a chemical reaction
B) an induced voltage
C) an alternator
D) a transformer
Question 15 (1 point)
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Inverter based power sources are usually heavy and bulky. (True/False)
Question 15 options:
True
False
Question 16 (1 point)
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The formula for the Ohm's law is: (Multiple Choice)
Question 16 options:
A) I = V/R
B) I = R/V
C) V = R/I
D) RV = IR
Question 17 (1 point)
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A problem with reactively controlled welding machines is the low
power factor. What is the ideal power factor? (Multiple Choice)
Question 17 options:
A) 1 power factor
B) 0.7 power factor
C) 12 power factor
D) 0.5 power factor
Question 18 (1 point)
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An advantage of inverter based power sources is that the circuitry is
more simplified than the conventional transformer-based power source.
(True/False)
Question 18 options:
True
False
Question 19 (1 point)
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Select the correct statement. (Multiple Choice)
Question 19 options:
A) PAW utilizes a steel electrode
B) PAW utilizes a tungsten electrode
C) PAW utilizes a zirconium electrode
D) None of the above
Question 20 (1 point)
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An advantage of using tapped transformers is: (Multiple Choice)
Question 20 options:
A) it only uses DC current.
B) it only uses AC current.
C) it only provides specific current settings.
D) None of the above
Question 21 (1 point)
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When a sufficient amount of energy is imparted to the atom in a gas,
this energy produces: (Multiple Choice)
Question 21 options:
A) an atomic reaction.
B) gamma rays.
C) free electrons and positively charged ions.
D) gamma and beta rays.
Question 22 (1 point)
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What is the component that is used in DC circuits to store and release
voltage according to the circuit requirements? (Multiple Choice)
Question 22 options:
A) Microprocessors
B) Diodes
C) Resistors
D) Capacitors
Question 23 (1 point)
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What is the effect of frequency modulation when transistors are used
for a DC power supply? (Multiple Choice)
Question 23 options:
A) Changes in wire feed speed cause an increase in heat input
B) Widening of the arc
C) Increased droplet size
D) Increase puddle fluidity
Question 24 (1 point)
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Power supplies are selected by process only without consideration of
material type and thickness. (True/False)
Question 24 options:
True
False
Question 25 (1 point)
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Examples of insulators are: (Multiple Choice)
Question 25 options:
A) plastics, semiconductors, and many ceramics
B) rubber, plastics, and many ceramics
C) semiconductors, rubber, and many ceramics
D) gas, semiconductors, and rubber
EXAM 2
Question 1 (1 point)
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Which was the first welding power source design to incorporate a
feedback circuit? (Multiple Choice)
Question 1 options:
A) Inverter
B) Mechanical reactor
C) Silicon-controlled rectifier
D) Saturable reactor
Question 2 (1 point)
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Gases are not normally electrically conductive. To start an arc requires:
(Multiple Choice)
Question 2 options:
A) high voltage.
B) high inductance.
C) high current.
D) AC power.
Question 3 (1 point)
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A pulsating weld pool that grows and shrinks significantly with each
pulse produced by the power source results in: (Multiple Choice)
Question 3 options:
A) lower penetration.
B) greater penetration.
C) a very large puddle.
D) a very small puddle.
Question 4 (1 point)
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The self regulating arc created by a constant voltage power supply is
most commonly associated with a constant speed wire feeder. With this
type of equipment: (Multiple Choice)
Question 4 options:
A) when arc length increases, wire feed speed increases.
B) when arc length increases, welding current decreases.
C) when arc length increases, welding current increases.
D) when arc length decreases, welding current decreases.
Question 5 (1 point)
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How is the dynamic characteristic of a power source controlled?
(Multiple Choice)
Question 5 options:
A) By voltage
B) By contact tip to work distance
C) By resistance and inductance
D) By current capacity
Question 6 (1 point)
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Inverter welding power sources have a very short response time
because: (Multiple Choice)
Question 6 options:
A) the inverter operates at high frequencies.
B) there is no inductor (choke).
C) the output voltage is high.
D) feedback is not used.
Question 7 (1 point)
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Transformers designed for higher frequencies require much less iron
core and windings than those designed for low frequencies. How is this
frequency created? (Multiple Choice)
Question 7 options:
A) By using the inverter principle to create high frequency AC
B) By adding a high frequency stabilizing circuit to the output circuit
C) By placing the rectifier on the output side of the transformer
D) By placing metal oxide varistors in parallel with the inlet rectifier
Question 8 (1 point)
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What is the term for voltage measured across the output terminals of a
welding machine when no current is being drawn? (Multiple Choice)
Question 8 options:
A) diode voltage
B) operating voltage
C) open circuit voltage
D) terminal voltage
Question 9 (1 point)
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Impedance is: (Multiple Choice)
Question 9 options:
A) the algebraic sum of resistance, capacitance, and inductance.
B) the sum of resistance and inductance.
C) the algebraic sum of capacitance and resistance.
D) none of the above.
Question 10 (1 point)
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Does Ohm's law apply to the welding arc? (Multiple Choice)
Question 10 options:
A) Yes
B) No
Question 11 (1 point)
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In some situations with the SMAW process, such as manual welding of
pipe joints, a flatter slope is used to provide some change in current
when arc lengths changes. (True/False)
Question 11 options:
True
False
Question 12 (1 point)
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How much do the labour and overhead costs account for welding
production? (Multiple Choice)
Question 12 options:
A) 50%
B) 80%
C) 30%
D) 57%
Question 13 (1 point)
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The first CC welding power source to allow current adjustment remote
from the power sources was a __________________power source.
(Multiple Choice)
Question 13 options:
A) silicon controlled rectifier
B) mechanical reactor
C) tapped transformer
D) saturable reactor
Question 14 (1 point)
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What two components are used for microprocessor control? (Multiple
Choice)
Question 14 options:
A) Transistors and electronic amplifiers
B) Saturable reactors and diodes
C) Feedback circuits and amplifiers
D) Gates and transistors
Question 15 (1 point)
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What is the minimum number of diodes necessary to produce a full-
wave rectified waveform? (Multiple Choice)
Question 15 options:
A) 5 diodes
B) 4 diodes
C) 1 diode
D) 3 diodes
Question 16 (1 point)
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The first application of pulsed GMAW welding power sources was to:
(Multiple Choice)
Question 16 options:
A) provide low energy in the arc.
B) allow the spray transfer mode to be used in out of position welding.
C) limit the amount of spatter produced in the short circuit transfer mode.
D) provide balanced arc starting.
Question 17 (1 point)
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Is the dirt inside a power source likely to create a short circuit?
(Multiple Choice)
Question 17 options:
A) Yes
B) No
Question 18 (1 point)
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With a constant current power source, the steeper the slope: (Multiple
Choice)
Question 18 options:
A) the more the current will vary.
B) the current will not vary.
C) the less control of current.
D) the less the current will vary
Question 19 (1 point)
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High frequency arc starting circuits use a __________________ to
generate the high frequency. (Multiple Choice)
Question 19 options:
A) spark gap
B) high speed switching transistors
C) inverters
D) SCRs
Question 20 (1 point)
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What type of output current is usually required for welding with the
GTAW process? (Multiple Choice)
Question 20 options:
A) Constant voltage
B) Very high open circuit voltage
C) Low power factor
D) Constant current
Question 21 (1 point)
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Why is transformer used as a power source for welding ? (Multiple
Choice)
Question 21 options:
A) It provides high resistance to current
B) It provides low voltage and high current
C) It provides high magnetic field
D) Iit provides high impedance
Question 22 (1 point)
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The two systems that can be used to adjust the output of a transistor
welding power source are: (Multiple Choice)
Question 22 options:
A) tapped transformer and SCR.
B) SCR and inverter.
C) frequency and pulse width modulation.
D) peak voltage and current feedback.
Question 23 (1 point)
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Factors that facilitate the initiation of an arc starting in a welding
machine are: (Multiple Choice)
Question 23 options:
A) welder skill and magnetic field
B) type of electrode and current
C) open circuit voltage
D) the power factor of the welding machine and voltage
Question 24 (1 point)
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The capacity to store and recall detailed welding variables in a welding
power source is possible due to: (Multiple Choice)
Question 24 options:
A) SCR controls.
B) saturable reactors.
C) feedback circuits.
D) microprocessor controls.
Question 25 (1 point)
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What is meant by duty cycle?
Question 25 options:
the length of time a diode can conduct electricity
how long a contact tip will last
the number of minutes, within a 10 minute period, during which a given welder can safely produce a
particular welding current
the expected life of a welding power source
EXAM 2
Question 1 (1 point)
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What is the V-I characteristic of a power source? (Multiple Choice)
Question 1 options:
A) The rate of current rise once the arc is struck
B) The value of the open circuit voltage
C) The machine's rated output current at rated duty cycle
D) The power source curve showing the voltage and current output
Question 2 (1 point)
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Which of the following methods is commonly used to control the
output of a transformer? (Multiple Choice)
Question 2 options:
A) An auxiliary power supply that feeds the secondary as required.
B) A saturable reactor
C) Resistance placed in parallel with the primary of the transformer
D) Taps on the secondary of the transformer
Question 3 (1 point)
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The GTAW process is considered a: (Multiple Choice)
Question 3 options:
A) consumable electrode process.
B) process requiring low skill.
C) process that uses CC output.
D) process requiring a strong acting flux.
Question 4 (1 point)
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Why is it necessary for the power source to provide a large open
circuit voltage ? (Multiple Choice)
Question 4 options:
A) To be able to initiate the arc
B) To penetrate deeper within the material
C) To help with the deposition rate
D) To produce quality welds
Question 5 (1 point)
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The main components used to rectify are: (Multiple Choice)
Question 5 options:
A) diodes.
B) transistors.
C) inductors.
D) transformers.
Question 6 (1 point)
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The first welding power source was developed using: (Multiple Choice)
Question 6 options:
A) a DC generator.
B) a transformer.
C) transformer rectifier.
D) lead acid batteries.
Question 7 (1 point)
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Wire feed systems that employ constant current control the arc by:
(Multiple Choice)
Question 7 options:
A) resistance
B) low conduction
C) voltage sensing
D) reactance
Question 8 (1 point)
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An advantage of SCR welding power sources is the ability to
incorporate feedback circuits to provide strict control on the output.
(True/False)
Question 8 options:
True
False
Question 9 (1 point)
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The duty cycle of a welding power supply is based upon delivering its
rated output for a given number of minutes out of a 10 minute period.
Which of the following statement is correct? (Multiple Choice)
Question 9 options:
A) A 300 amp/60% duty cycle machine is rated to deliver 300 amps for 6 minutes in a ten minute period.
B) A 300 amp/30% duty cycle machine is rated to deliver 300 amps in a ten minute period.
C) A 250 amp/30% duty cycle machine is rated to deliver 250 amps for 30 minutes.
D) A 300 amp/60% duty cycle machine is rated to deliver 500 amps maximum for 6 minutes in a ten
minute period.
Question 10 (1 point)
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For an ideal CC welding power source, an SMAW welder can indirectly
increase the energy in the arc without changing the power source
setting by: (Multiple Choice)
Question 10 options:
A) maintaining a short arc.
B) maintaining a long arc.
C) travelling faster.
D) changing the electrode size.
Question 11 (1 point)
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What is the most common power output for SMAW process? (Multiple
Choice)
Question 11 options:
A) DCEN
B) DCEP
C) AC
D) AC balanced
Question 12 (1 point)
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It is essentially impossible to maintain a stable welding arc with the
SMAW process and a constant voltage power source. (True/False)
Question 12 options:
True
False
Question 13 (1 point)
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What is the force or pressure that causes current to flow through an
electric circuit? (Multiple Choice)
Question 13 options:
A) Resistance
B) Inductance
C) Reactance
D) Electrical potential
Question 14 (1 point)
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One of the major advantages of inverter welding power sources is:
(Multiple Choice)
Question 14 options:
A) low initial cost.
B) small size and low weight.
C) no need for feedback control.
D) high input voltages.
Question 15 (1 point)
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What does IGBT stand for in welding? (Multiple Choice)
Question 15 options:
A) insulated-gate bipolar transistor
B) insulate-gate bipolar thyristor
C) insulated-gap bipolar transistor
D) None of the above
Question 16 (1 point)
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Conventional transformer-rectifiers rectify AC current on the
secondary side of the transformer at lower voltage and higher current.
(True/False)
Question 16 options:
True
False
Question 17 (1 point)
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What are the possible causes if the arc stops and starts during welding?
(Multiple Choice)
Question 17 options:
A) Machine overload and the duty cycle is too low
B) An inert gas is too highly concentrated
C) Machine overload and the duty cycle is too high
D) Welding cables are too large
Question 18 (1 point)
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In GTAW high frequency systems, incoming AC line voltage is stepped
up to several thousand volts by a transformer. Select the correct
statement. (Multiple Choice)
Question 18 options:
A) High frequency systems are limited to less than 4,000 volts for safety reasons
B) The spark gap needs to be at least 75 mm (3 in) wide for the spark to jump far enough to create the arc
C) High frequency systems output high voltage but only low current
D) High frequency systems only work with DC arcs
Question 19 (1 point)
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What is the preferred polarity for GMAW and FCAW? (Multiple Choice)
Question 19 options:
A) DCEN
B) DCEP
C) AC
D) AC balanced
Question 20 (1 point)
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When the core of a welding transformer is moved to adjust the output,
this type of control is called a: (Multiple Choice)
Question 20 options:
A) moving secondary.
B) tapped transformer.
C) moving shunt.
D) saturable reactor.
Question 21 (1 point)
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Two examples of good semi-conductors are: (Multiple Choice)
Question 21 options:
A) copper and silicon.
B) silicon and germanium.
C) selenium and aluminum.
D) germanium and steel.
Question 22 (1 point)
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Constant current type power sources exhibit a significant drop in
________________as current draw increases. (Multiple Choice)
Question 22 options:
A) arc blow
B) spatter
C) puddle fluidity
D) voltage
Question 23 (1 point)
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Which of the following welding processes would be a better choice for
welding a two-inch material with double V preparation? (Multiple
Choice)
Question 23 options:
A) FCAW
B) SMAW
C) PAW
D) SAW
Question 24 (1 point)
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Impedance is: (Multiple Choice)
Question 24 options:
A) the algebraic sum of resistance, capacitance, and inductance.
B) the sum of resistance and inductance.
C) the algebraic sum of capacitance and resistance.
D) none of the above.
Question 25 (1 point)
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Gases are not normally electrically conductive. To start an arc requires:
(Multiple Choice)
Question 25 options:
A) high voltage.
B) high inductance.
C) high current.
D) AC power.
