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Electrical Foundation > Everything Electricity > Flashcards

Everything Electricity Flashcards

1
Q

Name the three principal parts of an atom

A

Electron, proton, and neutron

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2
Q

A(n) ________ is a substance that cannot be chemically divided into two or more simpler substances

A

Element

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3
Q

All ________ is made from a combination of atoms

A

Matter

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4
Q

The atomic number of an element is equal to the number of ________ in the nucleus

A

Protons

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5
Q

Any electrons located in the outer shell of an atom are known as ________

A

Valence electrons

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6
Q

A conductor is made from a material that contains between ________ valence electrons

A

One to three

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7
Q

Materials containing seven or eight valence elctrons are known as ________

A

Insulators

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8
Q

________ are materials that are neither good conductors nor good insulators

A

Semiconductors

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9
Q

The smallest part of a compound is called a ________

A

Molecule

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10
Q

List the six methods for producing electricity

A

Magnetism, chemical action, pressure, heat, friction, and light

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11
Q

A(n) ________ is the smallest part of an element

A

Atom

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12
Q

State the law of charges

A

Opposite charges attract, while like charges repel

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13
Q

It is theorized that protons and neutrons are actually formed from a combination of smaller particles called ________

A

Quarks

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14
Q

True or false: Static charges accumulate on insulator materials

A

True

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15
Q

The word ________ means not moving or sitting still

A

Static

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16
Q

A current of 1 ampere delivered in one second is defined as ________

A

1 coulomb

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17
Q

The ampere (A) is equal to ________

A

1 coulomb per second

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18
Q

The electron flow theory states that current flows from the most ________ point in the circuit to the most ________

A

Negative to positive

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19
Q

The conventional current flow theory states that current flows from the most ________ point to the most ________

A

Positive to negative

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20
Q

Voltage can also be referred to as ________ and ________

A

Potential difference and electromotive force (EMF)

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21
Q

A volt is the amount of potential necessary to cause ________ to produce ________ of work

A

1 coulomb, 1 joule

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22
Q

A(n) ________ is the unit of resistance to current flow

A

Ohm

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23
Q

The amount of power being used in a circuit is measured by which unit

A

Watts

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24
Q

________ can be neither created nor destroyed, only transformed

A

Energy

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25
Q

________ is equal to power (kW) x time (hours)

A

Energy

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26
Q

________ is the transfer of energy from one object to another

A

Work

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27
Q

State Ohm’s law

A

Current is directly proportional to the voltage and inversely proportional to the resistance

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28
Q

1 watt equals ________

A

1 joule / second

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29
Q

True or false: An open circuit has infinite resistance

A

True

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30
Q

Before current can flow, a circuit must be ________

A

Complete / closed

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31
Q

A ________ circuit has little or no resistance

A

Short

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32
Q

What is a coulomb?

A

A coulomb is a measure of charge. It is defined as the charge transferred by a current of 1 ampere in one second

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33
Q

What is an ampere?

A

An ampere is equal to 1 coulomb per second

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34
Q

True or false: when current flows through a wire, a magnetic field is created around the wire

A

True

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35
Q

True or false: the direction of current flow through a wire determines the polarity of the magnetic field

A

True

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36
Q

List two common functions of resistors in a circuit

A

Limit the flow of current through a circuit and produce a voltage divider

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37
Q

________ resistors have only one ohmic value

A

Fixed

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38
Q

List 5 types of fixed resistors

A

Composition carbon, metal film, carbon film, metal glaze, and wire-wound

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39
Q

A ________ is a resistor whose values can be changed or varied over a range

A

Variable resistor

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40
Q

How many terminals are there in a rheostat?

A

Two

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41
Q

A potentiometer is a variable resistor that contains ________ terminals

A

Three

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42
Q

True or false: the value of fixed resistors can be varied

A

False

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43
Q

The primary advantage of wire-wound resistors over other fixed type resistors is their ________

A

High power rating

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44
Q

Name three types of fixed resistors

A

Carbon composition, carbon film, metal film, metal glaze, and wire-wound

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45
Q

How should a tubular wire-wound resistor be mounted and why?

A

Vertically. Air flow helps dissipate heat thereby keeping the resistor from over-heating

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46
Q

What is a potentiometer?

A

A three terminal variable resistor

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47
Q

A resistor has colour bands of orange, blue, yellow, and gold. What is the resistance and tolerance of this resistor?

A

360,000 ohm, +- 5%

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48
Q

A ________ is a circuit that has only one path for current to flow

A

Series circuit

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49
Q

True or false: fuses and circuit breakers are connected in series with the rest of the circuit

A

True

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50
Q

State the three rules that can be used with Ohm’s law for finding values of voltage, current, resistance, and power in any series circuit.

A
  1. The current is the same at any point in the circuit (It = I1 = I2 = I3 …)
  2. The total resistance is the sum of the individual resistors (Rt = R1 + R2 + R3 ….)
  3. The applied voltage is equal to the sum of the voltage drops across all the resistors (Et = E1 + E2 + E3 …)
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51
Q

True or false: current is the same at any point in a series circuit

A

True

52
Q

The ________ in any circuit is equal to the sum of the power dissipated by all parts of the circuit

A

Total power

53
Q

When multiple voltage sources are connected in series, the ________ pole of one source always connects to the ________ pole of another source

A

Positive to negative

54
Q

When series circuits are used for the purpose of obtaining different voltages from one voltage source, they are known as ________

A

Voltage dividers

55
Q

________ are circuits that have more than one path for current to flow

A

Parallel circuits

56
Q

True or false: In a parallel circuit, the total current flow is equal to the sum of the currents through all the branches

A

True

57
Q

True or false: The amount of current flow through each branch of a parallel circuit is inversely proportional to it’s resistance

A

True

58
Q

What characterizes a parallel circuit?

A

A circuit that has more than one path for current to flow

59
Q

Four resistors having a value of 100 ohm each are connected in parallel. What is the total resistance of the circuit?

A

25 ohm. Rt = R/N, Rt = 100/4, Rt = 25 ohm

60
Q

Describe the two key rules that must be followed when connecting voltage sources in parallel

A
  1. Voltage sources connected in parallel must have the same voltage rating
  2. Care should be taken to match polarities, positive to positive and negative to negative
61
Q

True or false: All parallel circuits are current dividers

A

True

62
Q

________ states that at any node, the algebraic sum of the currents will equal zero

A

Kirchhoff’s current law

63
Q

State Kirchhoff’s voltage law

A

In a closed circuit, the algebraic sum of the voltage sources and voltage drops must equal zero

64
Q

________ are circuits that contain both series and parallel branches

A

Combination circuits

65
Q

One of the most common analog meter movements is the ________ , also known as the moving-coil meter

A

D’Arsonval movement

66
Q

Name the 4 components of the d’Arsonval meter movement

A

A permanent magnet, pointer, spring, and moving coil

67
Q

Voltmeters have a very ________ resistance and are designed to be connected directly across the ________

A

High, source

68
Q

Ammeters have a ________ resistance and must be connected in _________ with a load to limit the flow of current

A

Low, series

69
Q

________ are used to measure the resistance in a circuit

A

Ohmmeters

70
Q

True or false: It is safe to connect an ohmmeter, whether digital or analog, to a circuit when the power is turned on

A

False. Ohmmeters use their own internal power supply and have a very low operating voltage. Connecting an ohmmeter to power will probably damage or even destroy the meter

71
Q

Name the four factors that determine the resistance of a length of wire

A

Material, diameter, length, and temperature

72
Q

Materials that increase their resistance with an increase of temperature have a ________ temperature coefficient

A

Positive

73
Q

Materials that decrease their resistance with an increase of temperature have a ________ temperature coefficient

A

Negative

74
Q

A ________ is a cell that cannot be recharged

A

Primary cell

75
Q

True or false: A secondary cell can be recharged

A

True

76
Q

The amount of current a particular type of cell can deliver is determined by ________

A

The surface area of its plates

77
Q

The amount of energy a cell can deliver is called its ________

A

Current capacity

78
Q

The device produced by the joining of two dissimilar metals for the purpose of producing electricity with heat is called a ________

A

Thermocouple

79
Q

________ is produced by some materials when they are placed under pressure

A

Piezoelectricity

80
Q

A ________ converts chemical energy into electrical energy

A

Voltaic cell

81
Q

A ________ is a group of cells connected together

A

Battery

82
Q

The amount of energy a battery can contain is called its ________ or ________

A

Current capacity, energy density

83
Q

A ________ is a device for measuring the specific gravity of an electrolyte

A

Hydrometer

84
Q

When lead-acid batteries are charged, ________ is produced

A

Hydrogren gas

85
Q

True or false: When cells are connected in series, their voltages remain the same and their ampere-hour capacities add

A

False. When voltages remain the same and ampere-hour capacities add, cells are connected in parallel

86
Q

True or false: It is safe to connect batteries of different voltages in parallel

A

False

87
Q

The basic function of a ________ is to open and close a circuit

A

Switch

88
Q

Switches have 6 possible ratings, 3 of which are mandatory on all switches regardless of their application. What are the 3 ratings?

A

Voltage, amperes, and CSA (Canadian Standards Association) approval

89
Q

A SPDT switch is also known as a ________

A

Single pole double throw, or a three-way switch

90
Q

A ________ is designed to prevent dangerous shocks and protects against over-current situations

A

Ground fault circuit interrupter (GFI)

91
Q

A GFI unit is able to detect a leakage of current as low as ________

A

2 mA (0.002 A)

92
Q

A ________ is a current sensitive device designed to limit current flow and protect the conductors in a circuit

A

Fuse

93
Q

Ohm’s Law states that the current is directly proportional to the ________ and inversely proportional to the ________

A

Voltage, resistance

94
Q

The kilowatt-hour is a unit of ________

A

Energy

95
Q

The term ________ refers to the generation of electricity by pressure

A

Piezoelectric effect

96
Q

The term triboelectric effect refers to the generation of electricity by ________

A

Friction

97
Q

The device that generates electricity from the sun’s energy is called a(n) ________

A

Photovoltaic cell

98
Q

The majority of electrical energy is produced by ________

A

Magnetism

99
Q

What is the main advantage of using stranded wire versus solid wire

A

Flexibility

100
Q

What are the common problems associated with aluminum when using it as a conductor?

A

Oxidization, cold flow (similar to annealing), and electrolysis

101
Q

What is the moisture absorbing effect of varnished cambric called

A

Hygroscopic

102
Q

What is the main advantage of using MI cable?

A

High heat resistance

103
Q

MI Cable has a common ‘trade name’ known as ________

A

Pyrotenex

104
Q

Conductors that lay flat and typically run underneath carpet are classified as ________

A

FCC, flat conductor cable

105
Q

A conductor labelled ‘ACWU’ is suitable for use in ________ and ________ environments

A

Wet, underground

106
Q

________ is a property that describes the ability of a material to be stretched, pulled, or drawn into a thin wire or thread without breaking

A

Ductility

107
Q

________ refers to the ability of a conductor to carry current

A

Ampacity

108
Q

The ampacity of a conductor is determined by these 3 factors

A

Material, size (or area), and insulation

109
Q

________ is one of the most common insulator materials used for residential and industrial wiring

A

Thermoplastic

110
Q

What type of insulation is used on wire in the manufacture of windings for transformers, motors, and relays?

A

Enamel insulation

111
Q

A ________ is a variable resistor with 3 terminals

A

Potentiometer

112
Q

1 mil equals ________ inches

A

0.001, (1 one-thousandth)

113
Q

A substance that is made of atoms of more than one type is a ________

A

Compound

114
Q

Anything that occupies space or has mass is referred to as ________

A

Matter

115
Q

The atomic number of an element refers to the number of ________ in the ________ of an atom

A

Protons; nucleus

116
Q

The smallest part that a substance can be broken down into and still possess the same properties of the substance is a ________

A

Molecule

117
Q

________ current is described as unidirectional

A

Direct

118
Q

Alternating current is described as ________

A

Bidirectional

119
Q

Why is it not recommended that an overcurrent device be installed in the neutral conductor of a three-wire circuit?

A

It may open and create unbalanced voltages across the loads

120
Q

What is the main reason for grounding the midpoint (neutral point) of a 3 wire supply?

A

To reduce the shock hazard to less than line to line value

121
Q

In a parallel circuit, increasing the number of branches will cause the circuit ________ to increase and the circuit ________ to decrease

A

Power; resistance

122
Q

A common conductor insulation suitable for use in wet and dry locations is type ‘TW’. The letter ‘W’ indicates “wet” and the ‘T’ indicates ________

A

Thermoplastic

123
Q

In “type NMD90”, what does the 90 refer to?

A

Temperature

124
Q

The standard residential voltages of a three-wire system are ________

A

120V/240V

125
Q

True or false: A three-wire cirucuit is said to be unbalanced when the line conductors carry equal currents

A

False. This describes a balanced three-wire circuit. Unbalanced three-wire circuits have line conductors that carry different values of current

126
Q

In an unbalanced three-wire circuit, line one carries 7 amps and line two carries 13 amps. Using Kirchhoff’s Current Law, the current in the neutral carries how many amps?

A

6 amps

127
Q

________ is the rate at which work is done

A

Power

Electrical Foundation (12 decks)

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