Ultimate Industrial Electrical

Which frequency is a harmonic of 60 Hz? 10 Hz 30 Hz 90 Hz 180 Hz

180 Hz

If a transformer's primary winding has 200 turns and the secondary winding has 600 turns, the turns ratio is ____. 1:4 4:1 1:3 3:1

1:3

The starting torque of a shunt motor is about ____ times the full-load torque. 1.75 2.00 2.75 3.00

2.75

What is the approximate percentage of light reflected by a black colored surface? 3 percent 10 percent 50 percent 80 percent

3 percent

The effect of a harmonic on the current flowing in the supply conductors is approximately ____ percent. 10 3 to 5 40 to 50 90

3 to 5

What is the correct way to write the number 3,404,655 using scientific notation? 3.404655 x 10⁶ 34.04655 x 10⁷ 3.404655 x 10³ 3.404655 x 10⁻⁶

3.404655 x 10⁶

It has been proven that currents as small as ____ milliamperes through the heart, lungs, or brain can be fatal. 15 50 5 25

50

A common design practice is to allow a circuit breaker to carry only ____ percent of its continuous current rating. 60 70 80 90

80

A correction factor is used for the ampacity of conductors in installations where the operating temperature is above ____ degrees Fahrenheit. 32 68 86 100

86

The effect of a harmonic on the current flowing in the neutral conductor is approximately ____ percent. 10 3 to 5 40 to 50 90

90

What is the temperature rating for conductors enclosed in nonmetallic-sheathed cable? 70 degrees Celsius 80 degrees Celsius 90 degrees Celsius 100 degrees Celsius

90 degrees Celsius

The efficiency of a transformer may be as high as ____ percent. 85 90 99 100

99

What purpose does brush-shifting accomplish in a motor? Adjusts the rotor speed Compensates for hysteresis Changes the frequency Allows it to operate on AC or DC

Adjusts the rotor speed

Which NEC Article covers grounding locations and methods? Article 79 Article 220 Article 250 Article 429

Article 250

Heat energy can be measured in ____. degrees Celsius British thermal units ohms watts

British thermal units

____ connect the commutator to the load conductors. Brushes Alternators Laminations Yokes

Brushes

____ fuses are the type most commonly used in industrial installations. Plug Two-way Replaceable Cartridge

Cartridge

____ windings eliminate armature reaction. Compensating Conducting Alternating Brushless

Compensating

____ are similar to the electric furnace, but instead of having all the elements in one location, they are installed in the ducts for each specific area. Electric heating cables Convection heaters Baseboard heaters Duct heaters

Duct heaters

A generator's coils produce the most voltage when they move parallel to the magnetic lines of force. True False

False

A good commutator will have a very dark brown film of oxide. True False

False

A light intensity curve can be used to show that the amount of illumination is independent of the angle from the source. True False

False

A loop distribution system is an electrical transmission system that begins at a central station and supplies power to various substations. True False

False

Another name for metal-clad cable is Romex. True False

False

Armored cable has a flexible metallic enclosure. True False

False

Because the armature of a DC motor is wound in much the same way as a DC generator, the current from the supply must divide and flow through three or more paths. True False

False

Conduction heating is a method by which heat is transferred through the air or a fluid. True False

False

Conduit bodies are used in a conduit system to allow access for the pulling of wires, contain splices, and allow for the mounting of devices (e.g., switches, receptacles, etc.). True False

False

Direct current is less expensive to produce and transmit than alternating current. True False

False

Mirrored glass reflects 99 percent of the light that strikes it. True False

False

Most residential installation circuits are protected against overcurrent by 25-ampere or larger fuses or circuit breakers. True False

False

One advantage of the wound-rotor induction motor compared to the squirrel-cage motor is that it has lower initial cost and maintenance costs. True False

False

One of the rules for residential wiring is to install a 200-ampere, three-wire or larger service for a single-family dwelling. True False

False

Scientific notation uses increments of 1000 as well as word abbreviations to make large and small numbers less confusing. True False

False

Small transformers, such as those used for doorbell and signal circuits, are usually very efficient. True False

False

The nucleus of an atom is made up of protons, which have a positive charge and neutrons, which have a negative charge. True False

False

The phase sequence describes the order in which the currents follow one another. True False

False

The primary goal of the NFPA is "to promote the science and improve the methods of electrical wiring." True False

False

The purpose of grounding is to limit the magnitude of current surges. True False

False

The resistance of a wire is inversely proportional to its length. True False

False

The standard frequency for power distribution in the U.S. is 120 Hz. True False

False

The stationary part of the generator is called the rotor. True False

False

The two main components of an induction motor are the stator and the conductor. True False

False

There is one accepted symbol for a fuse. True False

False

To provide a comfortable area, it is recommended to maintain a temperature of 68 degrees Fahrenheit (20 degrees Celsius) with a relative humidity of 15 percent. True False

False

Two basic types of windings are in general use for DC generator armatures: the lap winding and the parallel winding. True False

False

When transformers are constructed, the windings are often placed on separate legs to minimize flux leakage. True False

False

When using a knife to remove insulation from a conductor, the insulation should be cut at a right angle to the conductor. True False

False

Which type of ground-fault protection is generally used for three-wire, single-phase, and for three-phase installations? GFP GFCI fuse circuit breaker

GFP

What does the abbreviation GFP stand for? Ground-Field Protector Ground-Fire Prevention Ground-Fault Protector Ground-Flux Prevention

Ground-Fault Protector

____ heating is used for metal treatment and in some electric furnaces. Induction Resistance Arc Dielectric

Induction

____ heating is used for drying operations, food warming, and medical purposes. Resistance Arc Induction Infrared

Infrared

____ may be installed in a substation unit. Branch circuit conductors Isolation switches Main supply conductors Utility poles

Isolation switches

___ is the voltage drop caused by current flowing though the resistance of the wires. Power drop Wire drop Line loss Line drop

Line drop

Which type of cable is color coded for easy conductor size identification? USE cable NM cable MC cable AC cable

NM cable

NFPA 79 Electrical Standard for Industrial Machinery is a publication of the ____. Armored Cable Code National Electrician's Association National Electrical Code National Fire Protection Association

National Fire Protection Association

In a delta-connected alternator, the line voltage is equal to ____ times the phase voltage. 1.0 1.25 1.73 2.0

1.0

In a wye-connected alternator, the line voltage is equal to ____ times the phase voltage. 1.0 1.25 1.73 2.

1.73

____ utilizes the fact that current flowing through a material produces heat. Dielectric heating Resistance heating Induction heating Convection heating

Resistance heating

What is one factor that affects the output voltage of an alternator? Resistance of the stator windings The frequency of the emf produced The type of coil connection The phase sequence

Resistance of the stator windings

____ lighting fixtures transmit 60 percent to 90 percent of the light upward. Indirect Semi-direct Semi-indirect General diffusing

Semi-indirect

____ motors are designed to be used for jobs requiring minimum torque. Series Brushless DC Stepping Permanent magnet

Stepping

What instrument is used to determine whether the frequency of an alternator to be brought on line matches the frequency of the bus? Phase sequence meter Prime mover Period meter Synchroscope

Synchroscope

With direct drive, the driving machine and the driven machine may be mounted on the same shaft, or a(n) ____ may be used. reducer pulley shaft coupling gear shaft

shaft coupling

Electrons orbit the nucleus of an atom in arranged rings called ____ . spheres ovals shells capsules

shells

A(n) ____ is a place in the wiring system where conductors of opposite polarity make contact. grounded conductor fuse short circuit circuit breaker

short circuit

A(n) ____ generator is a type of self-excited generator in which the field and armature are connected in parallel. parallel compound shunt series

shunt

What type of electrical drawing is most often used to trace the flow of power through the drawing? pictorial diagram single-line drawing architectural drawing ladder diagram

single-line drawing

Which of these is one of the three common styles of switches used to control lights? single-pole double-pole two-way grounded

single-pole

The difference between the synchronous speed and the rotor speed is called the ____ of the rotor. differential frequency phase difference slip

slip

In a parallel circuit, the total circuit resistance will be ____ the smallest branch resistance. smaller than larger than equal to greater than or equal to

smaller than

A glow switch is also called a(n) ____. preheat energy saver heater starter

starter

If a transformer has a ratio of 10 to 1 (10:1), it is being used as a ____ transformer. step-up step-down buck-boost tapped

step-down

If a transformer increases the voltage, it is called a ____ transformer. step-up step-down buck-boost tapped

step-up

In a radial distribution system, the central station supplies power to the various ____. substations loops residential units industrial installations

substations

In a combination circuit, the ____ of all individual wattages will equal the total circuit wattage. sum difference product ratio

sum

Rigid metal conduit has a(n) ____ raceway of circular cross-section. threadable smooth insulated flexible

threadable

A ____ overcurrent device is a fuse or circuit breaker that opens the circuit much more quickly than the ordinary device does. two three four five

three

There are ____ general types of circuit breakers. two three four five

three

Electrical power, in watts, can be expressed as the product of current, in amperes and electrical pressure, in volts. True False

true

Power is a measurement of the rate of doing work. True False

true

Fuses and circuit breakers have ____ current ratings. two three four five

two

The operation of a motor depends upon the interaction between ____ magnetic fields. two three four six

two

How many paths for current flow are in a parallel circuit? zero one only one or two two or more

two or more

If the ungrounded (hot) conductor comes in contact with a metal enclosure that is not grounded, a ____ will be present between the enclosure and the ground. current voltage resistance reactance

voltage

A generator that maintains a nearly constant output voltage from no load to full load has excellent ____. voltage control voltage regulation efficiency responsiveness

voltage regulation

Arc heating is used in ____. space heating cooking welding medical applications

welding

What is the most frequently used publication of the National Fire Protection Association? The U.S. Electrical Specifications The National Electrical Code The Life Safety Code The Handbook for Electrical Safety in the Workplace

The National Electrical Code

A circuit must contain a minimum of three different elements: a power source, a complete path for current flow, and a load. True False

True

A commutator is a type of rotating switch that changes the connections to the load circuit at the same instant as the emf reverses in the armature. True False

True

A demand factor is the ratio of the maximum load used at any one time to the total connected load. True False

True

A digital multimeter can measure voltage, current, and resistance. True False

True

A ground-fault circuit interrupter is a device that senses a small imbalance of current between the ungrounded (hot) conductor and the grounded (neutral) conductor. True False

True

A megohmmeter can be used to conduct resistance tests to ground.

True

A transformer's audible hum is a result of the laminations and windings vibrating as the magnetic field alternates. True False

True

According to the electron theory of magnetism, electrons produce a magnetic field as they spin. True False

True

Atoms that have from one to four electrons in their last, or outer, shell are generally good conductors of electricity. True False

True

Candlepower and lumens are units of measurement of light emitted from a source. True False

True

Electrical energy is the product of power and time. True False

True

Heat radiation is accomplished when the heat rays are transmitted through space. True False

True

In a brushless DC motor, a special circuit is used to perform the commutation of the applied DC. True False

True

In a schematic diagram, the load is typically located at the bottom or right side of the drawing. True False

True

In a series circuit, the current is the same value throughout the entire circuit. True False

True

In resistance baseboard heating, both conduction and natural convection occur, along with a small amount of radiation. True False

True

In some types of DC motor arrangements, a flywheel assists the motor in driving the load. True False

True

Large industrial establishments may find it more economical to distribute power at voltages higher than 600 volts. True False

True

Line loss is power dissipated as heat. True False

True

Many electrical codes have been developed on the state, local, and national levels. True False

True

Most single-phase systems are supplied from a three-phase primary. True False

True

On the three-phase motor, the windings are arranged to produce a rotating magnetic field when connected to a three-phase source. True False

True

One type of luminaire is indirect. True False

True

Rubber and glass are good insulators. True False

True

Switch symbols are sometimes combined so that a more complex switch can be represented. True False

True

The GFCI operates on the principle that an equal amount of current is flowing through the two wires. True False

True

The coils of an air core transformer are wound on forms made of nonconducting materials. True False

True

The heat pump operates on a principle similar to a refrigerator. True False

True

The induction motor is the most common type of AC motor. True False

True

The rotating field of a large alternator receives its energy from the DC exciter, through slip rings. True False

True

The speed of the rotor of an induction motor depends upon the synchronous speed and the load it must drive. True False

True

The three classes of magnets are natural, artificial, and electromagnets. True False

True

The type of material from which the core is made affects the efficiency of the transformer. True False

True

The wye connection, sometimes called a star connection, is a method of connecting coils together inside the alternator. True False

True

When calculating the load, it is common practice to start with the branch circuits and combine their loads at each panel. True False

True

When considering multiple light sources, the amount of illumination at a given point is the sum of the light rays coming from all the units. True False

True

When magnetism is used to produce electricity, it makes no difference whether the conductor moves through the field or the magnetic field moves across the conductor. True False

True

When using a megohmmeter, an important safety precaution is not to touch the test leads during the measurement.

True

Which type of service entrance cable is identified for underground use? Type USE Type SE Type TL Type UL

Type USE

Underground feeder and branch-circuit cable is known as Type ____ cable. BC UFBC UC UF

UF

A voltage tester is also referred to as a(n) ____. O'scope Megger Meggy Wiggy

Wiggy

A luminaire is _____. a complete lighting unit a method of lighting the power source for a lighting unit the lamp portion of a lighting unit

a complete lighting unit

Arcing at the brushes may be the result of _____ improper voltage a dirty commutator loose parts a dirty lubricant

a dirty commutator

Overheated bearings may be the result of _____. improper voltage a dirty commutator loose parts a dirty lubricant

a dirty lubricant

A(n) ____ is a type of rotating switch stator prony brake armature commutator

commutator

In a balanced three-phase system, the power factor is the____ of the angle between the phase current and the phase voltage. sine cosine tangent hypotenuse

cosine

A ____ overcurrent device is a fuse or circuit breaker that opens the circuit much more quickly than the ordinary device does. current-limiting voltage-limiting fast-acting grounding

current-limiting

The amount of current flowing through a circuit is ____ proportional to the electromotive force (voltage) and ____ proportional to the resistance of the circuit. directly; inversely inversely; directly directly; directly inversely; inversely

directly; inversely

Another name for a rotary converter is a(n) _____ dynamotor multiphase alternator dynamometer alternator

dynamometer

The heat from a(n) _____ is transmitted primarily by radiation. electric baseboard heater heat pump electric furnace electric heating cable

electric heating cable

To prevent the possibility of unwanted load shifting when connecting compound generators in parallel, connect the series field of each machine to a common ____. neutral plane alternating bus equivalent circuit equalizer bus

equalizer bus

What does FMC stand for? flexible metal connectors fireproof mechanical connectors flexible metal conduit fittings made for conduit bodies

flexible metal conduit

The most common type of electric discharge lamp is the ____ lamp. incandescent high energy discharge fluorescent commercial

fluorescent

What unit of measurement is used to measure the amount of illumination on a surface? lumen candlepower watt foot-candle

foot-candle

When using the right hand rule for a motor, the thumb points in the direction of the ____. current field force lines of magnetic flux

force

An electrostatic generator develops a voltage using ____. induction chemicals friction light

friction

When lighting is so bright that it causes eye discomfort, it is said to produce ____. vapor glare intensity absorbed light

glare

The NEC applies to ____. automobiles ships aircraft government buildings

government buildings

In which section of an oscilloscope is the variable sec/div control found? horizontal section vertical section display section trigger section

horizontal section

Time is measured ____ on the oscilloscope graticule. vertically horizontally diagonally in three dimensions

horizontally

To replace lost moisture in the air, a(n) ____ may be used. induction fan exhaust fan humidifier dehumidifier

humidifier

The molecular motion caused by the magnetizing and demagnetizing of a transformer's core results in friction which produces heat. This heat loss plus the power loss caused by the magnetic lag is called the ____ loss. phase copper friction hysteresis

hysteresis

For pure metals such as silver, copper and aluminum, the resistance of a conductor ____ as the temperature increases. increases decreases remains unchanged changes only slightly

increases

Air core transformers are ____. efficient inefficient as efficient as iron/steel core transformers about 30 percent efficient

inefficient

Which law is used to calculate the intensity of light at a given distance from a source? square law inverse square law proportional law spherical law

inverse square law

Transformers used for power distribution are wound on cores made of ____. iron or steel nonconducting materials aluminum antimony

iron or steel

The ____ method for synchronizing alternators is generally used only for small operations or for laboratory experiments. phase sequence frequency meter lamp dark lamp dim

lamp dark

A(n) ____ winding is used to obtain high current capacity. wave lap parallel alternating

lap

At times, lights are controlled by ____ switches and relays. low-voltage inductive high-voltage four-pol

low-voltage

One method of transformer construction is to build up thin, flat sections called ____. intertwined coils pancake coils nested coils laminated coils

pancake coils

Single-phase, ____ motors are started by means of a low-resistance short-circuited coil placed around one tip of each pole.

permanent capacitor reversing resistance shaded-pole

One method of making a single-phase motor self-starting is to apply the ____ principle. phase-splitting current-splitting voltage-splitting resistance-splitting

phase-splitting

A(n) ____ diagram shows the relative physical location of the components, wires, and termination points. schematic ladder pictorial architectural

pictorial

What is one method of cooling a transformer? place in a tank of refrigerant place in an air-conditioned room place in a tank of water place in a tank of oil

place in a tank of oil

What is the most common insulating material used on conductors? copper silk aluminum plastic

plastic

A(n) ____ motor is an AC motor in which the rotor revolves at the same speed as the rotating magnetic field. high-frequency multispeed squirrel-cage polyphase synchronous adjustable-speed induction

polyphase synchronous

An instrument designed to measure torque is called a ____. rotational force meter torquometer torque wrench prony brake

prony brake

If two conductors carrying current in the same direction are placed near each other, the magnetic forces tend to ____. push them apart pull them together have no effect cancel each other out

pull them together

The ____ motor is a single-phase motor that starts based on the principle that like poles repel. universal repulsion-start, induction-run torque reversing split-phase

repulsion-start, induction-run

Which term applies to magnetism that remains in a material after being removed from the magnetizing influence? residual magnetism retentivity permeability magnetic saturation

residual magnetism

Opposition to the flow of electrons is called _____. voltage inductance conductance resistance

resistance

The amount of heat generated by current flowing through a conductor depends on the current value and the conductor's ____. length area resistance inductance

resistance

Which term describes the ability of a material to retain its magnetism after being removed from the magnetizing influence? residual magnetism retentivity permeability magnetic saturation

retentivity

To reverse the direction of rotation of the rotor, you would ____. reverse the polarity of one of the fields reverse the polarity of both of the fields increase the operating frequency attach a permanent capacitor

reverse the polarity of one of the fields

For a baseboard resistance heater, the ____ functions as the operating control. room thermostat humidistat safety control furnace

room thermostat

Frequency is calculated by taking the number of field poles on the alternator, multiplying by ____, and then dividing their product by 120. resistance of the stator windings in ohms winding current in amperes rotor speed in rpm field strength in volts

rotor speed in rpm

In a(n) ____ generator, the magnetization current for the field coils is supplied from a source outside of the generator. This supply may be another DC generator, batteries, or a rectifier. self excited separately excited shunt externally excited

separately excited

A ____ motor has a very high starting torque. series shunt combination permanent magnet

series

In the past, ____ generators were used extensively for series arc lighting, particularly for street lighting. parallel compound shunt series

series

To convert circular mils to circular millimeters, divide circular mils by ____. 10 25.4 1550 2550

1550

How much power is dissipated by an electric oven if 30 A flows through a resistance of 10 ohms? 9.2 W 7.52 kW 9 kW 9000 kW

9 kW

Electrical drawings are typically drawn with all components energized. True False

False

Flexible cords and cables are sufficient for the fixed wiring of a building. True False

False

In a circuit with light bulbs connected in parallel, if one light bulb burns out, all of the light bulbs will fail to light. True False

False

One of the rules for electric charges is that the strength of the attraction or repulsion between charged objects is directly proportional to the distance between them. True False

False

A feeder circuit consists of the conductors between the service equipment and the final branch-circuit overcurrent device. True False

True

Alternating current flows first in one direction and then in the opposite direction. True False

True

Because all materials have some ability to conduct magnetic lines of force, it is not practical to make a magnetic insulator. True False

True

Electrical symbols are a way to convey meaning while conserving space on a drawing. True False

True

The clamp-on ammeter can be used to measure both large and small amounts of current.

True

The total resistance of a parallel circuit is equal to the reciprocal of the sum of the reciprocals of the individual resistances. True False

True

To find the total resistance in a series circuit, you would ____ the individual resistances. add subtract multiply take the reciprocal of the sum of

add

One of the most common types of permanent magnets is made of ____. iron nickel alnico steel

alnico

Which term means coulombs per second? ohm ampere volt resistance

ampere

in a ladder diagram, where is the first component to operate usually located? at the top to the right at the bottom to the left

at the top

A(n) ____ is also known as an electromagnet. armature magnetite ore fragment coil core

coil

Architectural symbols can convey the number of electrical ____ necessary for proper operation of a device or piece of equipment. switches gates connectors conductors

conductors

In which section of an oscilloscope is the intensity control found? horizontal section vertical section display section trigger section

display section

Work equals force multiplied by ____. current power energy distance

distance

A(n) ____ produces a magnetic field.

electric current

In an electrical circuit, which term indicates the voltage generated by the source, such as a battery or generator? electrical pressure electromotive force resistance current pressure

electromotive force

Which of these is an example of a driven machine? steam turbine gasoline engine electric motor elevator

elevator

Efficiency is the ratio of the unused power output to the total power input. True False

false

Energy loss occurs whenever energy is destroyed or consumed. True False

false

One type of architectural drawing is the ____. ladder diagram floor plan pictorial diagram wiring diagram

floor plan

Which term describes the ability of a material to conduct lines of force? residual magnetism retentivity permeability magnetic saturation

permeability

Applying pressure to certain crystals to produce voltage is known as the ____ effect. photovoltaic piezoelectric thermoelectric chemical

piezoelectric

In order for an object to be in a charged state, which two particles must be in a state of imbalance? protons and electrons protons and neutrons neutrons and electrons atoms and molecules

protons and electrons

A(n) ____connected in series with a motor will both limit and control the starting current. alternator torque converter rheostat thermostat

rheostat

What type of drawing shows the actual electrical connections, but not the actual physical location of components? single-line drawing architectural drawing schematic diagram pictorial diagram

schematic diagram

What unit is used to measure rectangular conductors? circular mil square mil AWG area mil

square mil

The ____ of a motor is the amount of torque developed at the instant the motor is energized. starting torque opening torque initial torque rated load torque

starting torque

In a parallel circuit, the ____ of the individual branch currents will equal the total circuit current. difference product sum ratio

sum

In a series circuit, which resistor will dissipate the most wattage? the one with the smallest resistance the one with the largest resistance the second largest resistance they will all be the same

the one with the largest resistance

In a series circuit, which resistor will have the largest voltage drop? the one with the smallest resistance the one with the largest resistance they will all be the same the one with the median resistance

the one with the largest resistance

When using a PIRE wheel, you should select a formula in the quadrant of ____. Power the unknown variable Resistance a known variable

the unknown variable

How many basic types of oscilloscope probes exist? one two three four

three

With which type of drive will the driven gear rotate in the opposite direction from the driving gear? chain drive two-gear drive three-gear drive direct drive

two-gear drive

In which section of an oscilloscope is the variable volts/div control found? horizontal section vertical section display section trigger section

vertical section

An oscilloscope measures ____. resistance power current voltage

voltage

In a parallel circuit, the ____ across the individual branch circuits will be the same. resistance current voltage power

voltage

What does a flat horizontal line used with the symbol for motors and generators indicate? AC DC series field shunt field

DC

A series circuit can have multiple paths for current flow. True False

False

A voltage tester is more accurate in measuring voltage than a digital multimeter. True False

False

Air is the best conductor of magnetism. True False

False

All artificial magnets are permanent magnets. True False

False

The total current flowing in a circuit is equal to the total ____ applied to the circuit divided by the total ____ of the circuit. voltage; current resistance; current resistance; voltage voltage; resistance

voltage; resistance

To calculate the current flowing in a series circuit, divide the ____ by the ____. resistance; voltage power; resistance resistance; power voltage; resistance

voltage; resistance

What is one possible downside of oversizing a motor? wasted power excessive motor heating insulation breakdown tripping overcurrent devices

wasted power

Which technique is used to measure small amounts of current using a clamp-on ammeter? winding the conductor around one jaw of the ammeter placing the conductor between the jaws of the ammeter placing the conductor underneath the jaws of the ammeter winding the conductor around the main body of the ammeter

winding the conductor around one jaw of the ammeter

A pictorial diagram is also called a(n) ____ diagram. ladder component architectural wiring

wiring

For health and comfort, a relative humidity of ____ percent is desirable. 3 to 5 10 to 15 30 to 40 50 to 60

30 to 40

For which temperature is resistivity (K) defined?

32 degrees F 68 degrees F 86 degrees F 100 degrees F

The magnetic field of a two-pole induction motor completes ____ revolutions per minute when supplied with 60 Hz. 60 180 1800 3600

3600

The ____ of a conductor is limited by the temperature that its insulation can tolerate without deteriorating or losing its insulating quality. capacitance ampacity resistivity thermal constant

ampacity

Dielectric heating is based on the principle of ____. resistance forced air inductance capacitance

capacitance

A capacitor-start, induction-run motor called a(n) ____ motor is frequently used for installations requiring higher starting torque than is available from the resistance split-phase motor. induction split-phase single-phase capacitor resistance-start capacitor split-phase

capacitor split-phase

To minimize line drop, electrical services should be installed in a(n) ____ location to minimize the distance to the loads. outdoor top floor central remote

central

The ratio between the light that reaches the working plane and the light produced by the luminaire provides a constant known as the ____. coefficient of utilization efficiency maintenance constant usage coefficient

coefficient of utilization

A(n) ____ control permits all of the lights or specific groups of lights to be controlled from one location. residential selector universal selector two-way master selector

master selector

Fittings are primarily intended to perform a(n) ____ function. design safety electrical mechanical

mechanical

The prime mover in a motor-generator set is the _____. generator motor dynamotor armature

motor

The current decreases as the armature coils of a generator move through the ____ plane. Theoretically, the current drops to zero. null negative neutral neutronic

neutral

To determine the synchronous speed of a motor, multiple 120 by the frequency of the supply current in hertz and divide their product by the ____. output voltage in volts number of poles on the stator resistance of the rotor windings in ohms inductive reactance of the rotor in henries

number of poles on the stator

A(n) ____, highly polished, bright material reflects most of the light that strikes it. translucent colored thin opaque

opaque

One application of a phototransistor is a(n) _____. optical encoder circuit voltage regulator Hall-effect device voltage controller

optical encoder circuit

A(n) ____ is used for installations where heavy loads are used infrequently or where it is apparent that future demand may require additional loading. autotransformer instrument transformer tapped transformer buck-boost transformer

tapped transformer

When alternators are connected in parallel, the phase rotation of the alternator and the distribution bus must be ____. 90 degrees out of phase 120 degrees out of phase 180 degrees out of phase the same

the same

When current and resistance are known, how do you find voltage? Multiply current by resistance Divide current by resistance Divide resistance by current Take the square root of resistance divided by current

Multiply current by resistance

Which is the smallest AWG wire size? No. 0 No. 4 No. 26 No. 50

No. 50

When using an oscilloscope to make measurements, the first step is _____. initializing the scope connecting the probe to the circuit connecting the ground lead to circuit ground compensating the probe

initializing the scope

Before using a digital multimeter, you should ____. check the ground break the circuit compensate the probes inspect the meter and probes

inspect the meter and probes

Which material is often used to protect sensitive instruments from electromagnetic fields? iron nickel alnico steel

iron

According to the left-hand rule for a single conductor, when grasping a conductor in your left hand with your thumb extended in the direction of current flow, your fingers will point in the direction of the ____.

lines of force of the magnetic field

The unit of measurement for flux in a magnetic circuit is called the ____. resistance maxwell gilbert reluctance

maxwell

In engineering notation, 106 is know by the term ____. kilo nano tera mega

mega

What is the unit of measurement for resistance? ohm ampere volt coulomb

ohm