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OEC > Closed Book 1 > Flashcards

Closed Book 1 Flashcards

1
Q

What is the most frequently used wire size for interior wiring?

A

12 awg

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2
Q

Electric power is almost exclusively generated, transmitted, and distributed by three-phase systems because it ________.

A) costs less than single-phase apparatus
B) Is more efficient
C) uses less material for given capacity
D) All of the above

A

All of the above

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3
Q

An automatic device that operates at preset values is known as a _____.

A) fuse
B) relay
C) contactor
D) mercury switch

A

Relay

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4
Q

Electron is a greek word for _____.

A) heat
B) feather
C) stone
D) amber

A

Amber

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5
Q

What kind of instrument is an ammeter?

A) recording
B) DC meter
C) indicating
D) integrating

A

An indicating

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6
Q

The____ value is considered the most important value of a sine wave

A) peak
B) instantaneous
C) effective
D) average

A

Effective

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7
Q

The purpose of battery cells connected in parallel is to_____.

A) increase internal resistance
B) increase in voltage output
C) increase in current capacity
D) decrease in current capacity

A

Increase in current capacity

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8
Q

When two resistances are connected in series, _____.

A) voltage across them must be the same
B) current in each resistor will be the same
C) there will be no current in the circuit
D) they will become inductive

A

Current in each resistor will be the same.

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9
Q

A step-down transformer ______.

A) increases both the voltage and the current
B) lowers the current and increases the voltage
C) lowers the voltage and increases the current
D) lowers bothe the current and voltage

A

Lowers the voltage and increases the current.

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10
Q

Heat is a form of wasted electrical energy dissipated by _____.

A) inductance
B) capacitance
C) a diode
D) resistance

A

Resistance

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11
Q

When one resistance in a series circuit is open _______.

A) the voltage is zero across the open resistance
B) the current is zero in all the resistances
C) the current is maximum in the normal resistances
D) the current increases in the voltage source

A

The current is zero in all the resistances.

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12
Q

If the needle of the VOM will no longer align with the zero-ohm mark at the lowest range of resistance but will align on the other resistance ranges, the probable cause is the ___.

A) meter current is abnormal
B) needle is bent
C) terminals were interchanged
D) supply battery is weak

A

Supply battery is weak

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13
Q

A wire has a resistance of 5 ohms. What will be the resistance of another wire of the same material three times as long and half the cross sectional area?

A

30 ohms

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14
Q

A wattmeter measures ____.

A) AC power only
B) DC reactive power only
C) AC and DC power
D) none of these

A

AC and DC power

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15
Q

Which of the following can vary with AC but not DC?

A) voltage
B) frequency
C) power
D) magnitude

A

Frequency

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16
Q

A large series motor should not be started without some mechanical load on it because it will ____.

A) open the fuse or cb
B) draw too much current
C) spark heavily
D) develop excess speed and damage itself

A

Develop excessive speed and damage itself

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17
Q

An inductor works by _____.

A) introducing resistance in a circuit
B) charging a piece of wire
C) storing energy as a magnetic field
D) choking off high frequency AC

A

Storing energy as a magentic field

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18
Q

A cell that can not be recharged is a _____.

A) dry cell
B) wet cell
C) Secondary cell
D) primary cell

A

Primary cell

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19
Q

A measuring unit used to measure the diameter of circular mils in a wire is a _____.

A) wire guage
B) micrometer
C) millimeter
D) milliammeter

A

Micrometer

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20
Q

The start winding of a split-phase indution motor is switched out of the circuit by a device called _____.

A) proximity switch
B) zero speed switch
C) magnetic contactor
D) centrifugal switch

A

Centrifugal switch

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21
Q

An ideal step-up transformer with 100 turns in the primary and 2500 turns in the secondary carries a load of 2 amperes in the secondary winding. The current of the primary windings is _____.

A

50 amps

22
Q

A device used to remove sharp burres or rough edges is a _____.

A) hickey
B) bender
C) reamer
D) rotometer

A

Reamer

23
Q

The presence of current is only made known by the effects it produces. Three important effects are _____.

A) heating, magnetic and chemical
B) generation, chemical and electric shock
C) heating, magnetic and electrick shock
D) heating, electric shock and generation

A

Heating, magnetic and electric shock

24
Q

_____ is a wiring method using knobs, tubes, and flexible non-metallic tubing for the protection and support of single insulated conductors concealed in hollow spaces of walls and ceilings of buldings.

A) knob and tube wiring
B) open wiring on insulators
C) open wiring with knobs, tubes, etc.
D) concealed knob and tube wiring

A

Concealed knob and tube wiring

25
Q

On a drawing, the letter B stands for_____.

A) buzzer outlet
B) pushbutton outlet
C) bell outlet
D) outlet with blank cover

A

Outlet with blank cover

26
Q

A ______ is not a standard fuse size.

A) 25
B) 75
C) 80
D) 125

A

75 amp

27
Q

_____ currents are wasteful currents that flow in the core of a transformer and produce heat.

A) sneak
B) magnetizing
C) eddy
D) residual

A

Eddy

28
Q

In electricity, the positive electric charge refers to _____.

A) atoms
B) electrons
C) neutrons
D) protons

A

Protons

29
Q

The rate of doing work is _____.

A) power
B) current
C) energy
D) force

A

Power

30
Q

A transformer consists of _____.

A) a parallel resonant circuit
B) two coils wound on a common core
C) a capacitor and an inductor
D) an inductance and resistance

A

Two coils wound on a common core

31
Q

The effects of a discharge of electricity due to ionization of surrounding air by high voltage is _____.

A) corona effect
B) hall effect
C) compton effect
D) miller effect

A

Corona effect

32
Q

An ammeter must always be connected in the circuit under test _____.

A) positive to negative and negative to negative
B) positive to positive and negative to positive
C) positive to negative and negative to positive
D) positive to positive and negative to negative

A

Positive to positive and negative to negative

33
Q

_____ is the poorest conductor of electricity.

A) steel
B) aluminum
C) silver
D) carbon

A

Carbon

34
Q

A meter used to test the armatures and stators of electric motors, generators, and other equipment for a short circuit is a _____.

A) multimeter
B) megohmeter
C) bolometer
D) growler

A

Growler

35
Q

In a transformer, the primary circuit sees the impedance of the _____ winding.

A) secondary
B) primary
C) both primary and secondary
D) isolation

A

Both primary and secondary

36
Q

When the temperature of a conductor is decreased, the resistance will be _____.

A) increased
B) steady
C) decreased
D) zero

A

Decreased

37
Q

_____ is the process by which one conductor produces or induces a voltage in another conductor even though there is no mechanical coupling between the two conductors.

A) cutting of fluxes
B) short cicuit
C) induction
D) eddy current

A

Cutting of fluxes

38
Q

A/an _____ motor has no commutator.

A) shunt
B) induction
C) universal
D) repulsion

A

Induction

39
Q

The inert gas present in an incandescent bulb is primarily intended to _____.

A) increase lumen output
B) decrease filament evaporation
C) activate the surface of the filament
D) reduce hazards when the glass bulb is shattered

A

Increase lumen output

40
Q

A short circuit can be detected by using _____.

A) a megger
B) an ammeter
C) an oscilloscope
D) an ohmeter

A

An ohmmeter

41
Q

Which of the following has the least amount of valance electrons?

A) insulator
B) semi-insulator
C) conductor
D) semiconductor

A

Conductor

42
Q

To increase voltage output, battery cells are connected in _____.

A) series
B) parallel
C) series-parallel
D) parallel-series

A

Series

43
Q

If a low resistance is connected in parallel with a higher resistance, the combined resistance is _____.

A) always less than the low resistance
B) always more than high resistance
C) always between the values of high and low resistance
D) higher or lower than the low resistance depending on the value of the higher resistance

A

Always less than the low resistance

44
Q

The purpose of the ballast in a fluorescent lamp assembly is _____.

A) to regulate the lumens output
B) to limit the current through the lamp
C) to improve the overall power factor
D) to regulate the voltage across the lamp

A

To limit the current through the lamp

45
Q

Branch circuits are classified according to the maximum _____.

A) power consumed
B) voltage across it
C) load being served
D) setting of the overcurrent device

A

Setting of the overcurrent device

46
Q

A capacitor opposes changes in _____.

A) current
B) voltage
C) voltage and current
D) neither voltage nor current

A

Voltage

47
Q

On a simple ohmmeter, the ohm mark is located _____.

A) in the middle
B) at the far left
C) at the far right
D) anywhere

A

At the far right

48
Q

Which of the following is the main focus of a DC motor?

A) to change mechanical energy into electrical energy
B) to change electrical energy into mechanical energy
C) to change chemical energy into mechanical energy
D) to generate power

A

To change electrical energy to mechanical energy

49
Q

A short length of conductor used to make a connection between terminals or around a break in the circuit is a _____.

A) jumper
B) bonding wire
C) tie wire
D) guy wire

A

Jumper

50
Q

A fuse link should be made from a material with a _____ melting point.

A) high
B) low
C) moderate
D) strong

A

Low

OEC (5 decks)

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