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OEC > Closed Book 4 > Flashcards

Closed Book 4 Flashcards

1
Q

The electromotive force required to cause a current to flow may be obtained _____.
I. thermally
II. mechanically
III. chemically

A

All

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2
Q

Which of the following is not true?
A) A fluorescent fixture is more efficient than an incandescent fixture.
B) Room temperature has an affect on the operation of a fluorescent lamp.
C) Fluorescent fixtures have a good power factor with the current leading the voltage.
D) The life of a fluorescent bulb is affected by starting and stopping

A

Fluorescent fixtures have a good power factor with the current leading the voltage.

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3
Q

Resistance opposes the flow of current in a circuit and is measured in _____.
A) farads
B) joules
C) ohms
D) henrys

A

Ohms

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4
Q

which of the following is true?
A) Wooden plugs may be used for mounting electrical equipment in concrete
B) The high leg conductor of a 4 wire delta is identified blue in color
C) the minimum size service permitted by the Code for a residence is 100 amps
D) the ungrounded conductor is connected to the screw shell of a lampholder

A

the minimum size service permitted by the Code for a residence is 100 amps

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5
Q

Multiple start buttons in a motor control circuit are connected in _____.
A) series
B) parallel
C) series-parallel
D) none of these

A

parallel

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6
Q

Which of the following is NOT true?
A) Feeder demand factors are applicable to household electric ranges
B) A green colored conductor can be used as an ungrounded conductor
C) insulated conductors #6 or smaller shall be white or gray, no marking tape permitted
D) all joints or splices must be electrically and mechanically secure before soldering

A

A green colored conductor can be used as an ungrounded conductor

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7
Q

Special permission is _____.
A) granted by the electrical foreman on the job
B) verbal permission by the inspector
C) given only once on one blueprint change request
D) the written consent of the AHJ

A

the written consent of the AHJ

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8
Q

One million volts can also be expressed as _____.
A) 1 millivolt
B) 1 kilovolt
C) 1 megavolt
D) 1 microvolt

A

1 megavolt

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9
Q

Resistance in a circuit may be _____.
I. resistance of the conductors
II. resistance due to imperfect contact
A) I only
B) II only
C) both I and II
D) neither I or II

A

both I and II

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10
Q

Which of the following is not true?
A) All receptacles on 15 and 20 amp branch circuits must be of the grounding type
B) Splices and joints shall be covered with an insulation equivalant to the conductor insulation
C) the size of the conductor determines the rating of the circuit
D) all 15 and 20 amp receptacles installed in a dwelling bathroom shall have GFCI protection

A

the size of the conductor determines the rating of the circuit

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11
Q

A universal motor has brushes that ride on the _____.
A) commutator
B) stator
C) inter-pole
D) field

A

commutator

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12
Q

How many kw hoursare soncumed by 25 - 60 watt light bulbs burning 5 hours in a 120v circuit?
A) 1.5
B) 180
C) 7.5
D) 75

A

7.5

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13
Q

A dynamo is _____.
A) a pole line insulator
B) a tool used to test dielectric strength
C) whenever current flows in the conductor
D) only if the conductor is formed into a loop

A

whenever current flows in the conductor

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14
Q

Which of the following is/are generally used for field magnets?
I. copper
II. steel
III. wrought iron
A) I and II only
B) I and III only
C) II and III only
D) I, II and III

A

I, II and III

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15
Q

The difference between a neutral and a grounded conductor is _____.
A) only a neutral will have equal potential to the ungrounded conductor
B) only a neutral’s outer covering is white or natural grey
C) only a neutral carries unbalanced current
D) there is no difference

A

only a neutral carries unbalanced current

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16
Q

The normal rotation of an induction motor is _____ facing the front of the motor. (the front of a motor is the end opposite the shaft)
A) clockwise
B) counterclockwise

A

counterclockwise

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17
Q

A magnetic field is created around a conductor _____.
A) whenever current flows in the wire, provided the wire is made of magnetic material
B) only when the wire carries a large current
C) whenever current flows in the conductor
D) only if the conductor is formed into a loop

A

whenever current flows in the conductor

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18
Q

A function of a relay is to _____.
A) turn on another circuit
B) produce thermal electricity
C) limit the flow of electrons
D) create resistance in the field windings

A

turn on another circuit

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19
Q

Which of the following is not true?
A) it is an electrical impossibility to have a circuit with only inductive reactance because the metallic wire has a resistance
B) the voltage of a circuit is the greatest effective difference of potential that exists between any two conductors of a circuit
C) the current is said to lag the voltage in a circuit that has only capacitive reactance
D) power factor is the phase displacement of current and voltage in an AC circuit

A

the current is said to lag the voltage in a circuit that has only capacitive reactance

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20
Q

Unity power factor, which means that the current is in phase with the voltage, would be _____.
A) .50
B) .80
C) .10
D) 1.0

A

1.0

21
Q

Rheostats and potentiometers are types of _____ resistors.
A) film
B) variable
C) fixed
D) wirewound

A

variable

22
Q

A laminated pole is _____.
A) one built up of layers or iron sheets, stamped form sheet metal an insulated
B) used in transmission lines over 800k
C) a pole soaked in creosote
D) found in the western part of the USA

A

one built up of layers or iron sheets, stamped form sheet metal an insulated

23
Q

Which of the following is true?
A) conductors of different systems may not occupy the same enclosure
B) knife switches should be mounted in a horizontal position
C) 75 amps is a standard fuse size
D) Circuits are grounded to limit excess voltage to ground, which might occur from lightning or exposure to other higher voltage sources

A

Circuits are grounded to limit excess voltage to ground, which might occur from lightning or exposure to other higher voltage sources

24
Q

Electrical power is a measure of _____.
A) work wasted
B) voltage
C) rate at which work is performed
D) total work performed

A

rate at which work is performed

25
Q

What percentage of the maximum (peak) voltage is the effective (RMS) voltage?
A) 100
B) 70.7
C) 63.7
D) 57.7

A

70.7

26
Q

A low factor is commonly caused by _____.
I. induction motors
II. synchronous motors
III. fluorescent lights
A) III only
B) II and III only
C) I and III only
D) I, II and III only

A

I and III only

27
Q

Which of the following is NOT true?
A) conduit painted with enamel cannot be used outdoors
B) All AC phase wires, neutral and equipment grounding conductors if used, must be installed in the same raceway
C) PVC shall have a minimum burial depth of 24”
D) EMT raceway can be installed in an air conditioning space heating duct

A

PVC shall have a minimum burial depth of 24”

28
Q

Which of the following is NOT true?
A) Equal currents flow in the branches of parallel circuits
B) the total resistance of a parallel circuit is less than the smallest resistor in the circuit
C) the total current in a parallel circuit is the sum of the branch currents
D) in a parallel circuit, there is more than one path for the current to flow

A

Equal currents flow in the branches of parallel circuits
B) the total resistance of a parallel circuit is less than the smallest resistor in the circuit

29
Q

Hysteresis is _____.
A) the tool used to read the specific gravity of a battery
B) the lagging of magnetism, in a magnetic metal, behind the magnetizing flux which produces it
C) the opposite of impedance
D) none of these

A

the lagging of magnetism, in a magnetic metal, behind the magnetizing flux which produces it

30
Q

The electric pressure of a circuit would be the _____.
A) voltage
B) amperage
C) resistance
D) wattage

A

voltage

31
Q

Permeability is?
A) the opposite of conductance
B) a measure of the ease with which magnetism passes through any substance
C) the total resistance to current flow
D) the liquid substance in a batter

A

a measure of the ease with which magnetism passes through any substance

32
Q

The Wheatstone bridge method is used for accurate measurement of?
A) voltage
B) amperage
C) resistance
D) wattage

A

resistance

33
Q

When a circuit breaker is in the OPEN position _____.
I. you have a short in the ungrounded conductor
II. you have a short in the grounded conductor
A) I only
B) II only
C) either I or II
D) both I and II

A

either I or II

34
Q

In solving series-parallel circuits, generally you would?
A) treat it as a series circuit
B) reduce it to its simplest form
C) assume that all loads are equal
D) treat it as a parallel circuit

A

reduce it to its simplest form

35
Q

A commutator is?
A) a ditching machine
B) the inter-poles of a generator
C) a device for causing the alternating currents generated in the armature to flow in the same direction in the external circuit
D) a transformer with a common conductor

A

a device for causing the alternating currents generated in the armature to flow in the same direction in the external circuit

36
Q

Which of the following is true?
A) EMT may be threaded
B) the “white” colored conductor connected to the silver colored post on a duplex receptacle on a 120v two-wire branch circuit is called the “neutral” conductor
C) plastic water pipe is approved to be used for electrical conduit
D) the screw shell of a lampholder may support a fixture weighing 6 pounds

A

the screw shell of a lampholder may support a fixture weighing 6 pounds

37
Q

To fasten a box to a terra cotta wall you should use which of the following?
A) wooden plug
B) lag bolt
C) expansion bolt
D) toggle bolt

A

toggle bolt

38
Q

If a 240v heater is used on 120v, the amount of heat produced will be?
A) twice as great
B) four times as great
C) 1/4 as much
D) the same

A

1/4 as much

39
Q

Which of the following about a strap is/are true?
I. you can turn pipe using one hand
II. use in a tight corner
III. use on different sizes of pipe
A) I only
B) II only
C) III only
D) I, II and III

A

I, II and III

40
Q

When soldering a joint, the flux is used to?
A) keep the wire cool
B) keep the surface clean
C) lubricate the joint
D) maintain a tight connection

A

keep the surface clean

41
Q

The transferring of electrons from one material to another would be?
A) electrochemistry
B) static electricity
C) solar electricity
D) piezoeletricity

A

static electricity

42
Q

A minimum thickness of _____ inch/inches of concrete over conduits and raceways should be used to prevent cracking.
A) 1
B) 2
C) 3
D) 4

A

1

43
Q

Wire connectors are generally classified as ____ type(s)
I. thermal
II. pressure
A) I only
B) II only
C) both I and II
D) neither I nor II

A

both I and II

44
Q

One of the disadvantages of indenter or crimp connectors is?
A) they must be re-crimped at each annual maintenance inspection
B) that special tools are required to make the joint
C) eventually they will loosen
D) they can only be used for copper conductors

A

that special tools are required to make the joint

45
Q

The usual service conditions under which a transformer should be able to carry its rated load are?
I. at rated secondary voltage or not in excess of 105% of the rated value
II. at rated frequency
III. temperature of the surrounding cooling air at no time exceeding 104 degrees and average temp of the surrounding cooling air during any 24 hour period not exceeding 86 degrees
A) I only
B) II only
C) III only
D) I, II and III

A

I, II and III

46
Q

Which of the following is NOT true?

A) An autotransformer may be used as part of the ballast for lighting circuits
B) A branch circuit can never be supplied through an autotransformer
C) the losses of the autotransformer are less than those of a two coil transformer
D) Autotransformers may be used as starting compensators for AC motors

A

A branch circuit can never be supplied through an autotransformer

47
Q

Conductors supplying two or more motors shall have an ampacity equal to the sum of the full load current of all the motors plus _____% of the highest rated motor in the group.
A) 25
B) 80
C) 100
D) 125

A

25

48
Q

The voltage of a circuit is best defined as?
A) the potential between two conductors
B) the greatest difference of potential between two conductors
C) the effective difference of potential between tow conductors
D) the average RMS difference between any two conductors

A

the effective difference of potential between tow conductors

49
Q

A wattmeter is connected in series-parallel

A

true

OEC (5 decks)

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