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CORE Exam

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HVAC Quiz on CORE Exam, created by David Brown on 08/07/2018.
David Brown
Quiz by David Brown, updated more than 1 year ago
David Brown
Created by David Brown over 6 years ago
105
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0

Resource summary

Question 1

Question
What is the volume of a room that measures 10ft by 20ft with an 8ft ceiling
Answer
  • 800
  • 1600
  • 2400
  • 3200

Question 2

Question
What is the CFM requirement for a 1800 ft2 house with 8 ft ceilings, if five air changes per hour are needed?
Answer
  • 400
  • 1200
  • 1600
  • 2400

Question 3

Question
what is them CFM requirement for an 2400 ft2 house with 8 ft ceilings, if five air changes per hour are needed.
Answer
  • 400
  • 1200
  • 1600
  • 2400

Question 4

Question
what is the cross sectional area of a 10-in round metal duct
Answer
  • 79 in2
  • 200 in2
  • 314 in2
  • 418 in2

Question 5

Question
how fast does air with a velocity pressure of 0.20in. w.g. move through a round duct
Image:
Core Flew Velocity (binary/octet-stream)
Answer
  • 400ft/min
  • 1200ft/min
  • 1600ft/min
  • 1800ft/min

Question 6

Question
how fast does air with a velocity pressure of 0.20in w.g. move through a square duct?
Image:
Core Flew Velocity (binary/octet-stream)
Answer
  • 400 ft/min
  • 1200 ft/min
  • 1600 ft/min
  • 1800 ft/min

Question 7

Question
What is the advantage of using a tube cutter to cut copper pipe?
Answer
  • it can cut hard or soft copper
  • it leaves no metal shavings to contaminate the system
  • it produces a clean, square cut
  • all of the above
  • only B & C

Question 8

Question
spring-type benders may be used on ________?
Answer
  • soft drawn copper
  • hard copper
  • all copper pipe
  • steel pipe

Question 9

Question
a flaring tool is used to _________.
Answer
  • make a mechanical joint in tubing
  • measure pipe diameters
  • remove burrs from piping
  • separate pipe fittings

Question 10

Question
a swaging tool is used to _________.
Answer
  • cut copper pipe
  • make a mechanical joint in tubing
  • remove burrs from piping
  • solder tubing without the use of couplings

Question 11

Question
what is one of the advantages of a glass-stem thermometer?
Answer
  • it is very accurate
  • it is very durable
  • it comes with a digital readout
  • all of the above
  • none of the above

Question 12

Question
in discussing human comfort, the temperature most commonly referred to is __________.
Answer
  • dew point
  • dry-bulb
  • wet-bulb
  • fahrenheit

Question 13

Question
a sling psychrometer uses two glass-stem thermometers. one measures dry-bulb, and the other measures ______.
Answer
  • dew point
  • enthalpy
  • relative humidity
  • wet-bulb

Question 14

Question
a standard refrigeration manifold uses what type of element to measure pressure?
Answer
  • bellows
  • bourdon tube
  • diaphragm
  • spring

Question 15

Question
what is the pressure range of a standard compound gauge on a refrigeration manifold?
Answer
  • 0 to 350 psi
  • 0 to 500 psi
  • 30in. Hg to 350 psi
  • 30in. Hg to 500 psi

Question 16

Question
what is the best tool for removing moisture and noncondensibles from a system before adding refrigerant
Answer
  • manifold gauge
  • micron analyzer
  • recovery machine
  • vacuum pump

Question 17

Question
a vacuum gauge reads pressure in ______.
Answer
  • inches of mercury
  • inches of water
  • microns
  • psia
  • psig

Question 18

Question
which of the following is NOT a method of leak detection?
Answer
  • soap bubbles
  • electronic
  • micronic
  • ultrasonic

Question 19

Question
to prevent the release of refrigerant into the atmosphere, while removing it from a system what tool is used?
Answer
  • recovery machine
  • recycling machine
  • reclaim machine
  • vacuum pump

Question 20

Question
an anemometer uses a small fan blade to measure ______?
Answer
  • air pressure
  • air velocity
  • air volume
  • static pressure

Question 21

Question
what is one of the advantages using silver rods for brazing copper?
Answer
  • a lower melting temperature is required
  • a propane torch is used
  • no flux is required
  • no nitrogen purge is needed

Question 22

Question
what agency regulates cylinders and chemicals transported in a service vehicle?
Answer
  • ASHRAE
  • DOT
  • EPA
  • OSHA
  • ICE
  • DMV
  • LOL
  • YOLO

Question 23

Question
What is the maximum safe storage temperature of a refrigerant cylinder filled to 80% capacity by weight?
Answer
  • 120 F
  • 125 F
  • 130 F
  • 135 F

Question 24

Question
which of the following classification of fire extinguishers should be used for an electrical fire?
Answer
  • a
  • b
  • c
  • d

Question 25

Question
which of the following categories could be considered a hazardous atmosphere in a confined space?
Answer
  • asphyxiation
  • flammable
  • toxic
  • all of the above

Question 26

Question
if a ladder is placed against a wall that is 20 ft tall, what is the proper distance away from the wall for the base of the ladder?
Answer
  • 3 ft
  • 4 ft
  • 5 ft
  • 6 ft

Question 27

Question
what is one of the most important safety precautions that you can take when working on electrical equipment
Answer
  • disconnect and lockout power before starting unless testing requires the power to be on
  • keep one hand in your pocket while working on the power
  • label all hot wires
  • wear gloves suitable for high voltages

Question 28

Question
when does a ground fault circuit interrupter open an electric circuit?
Answer
  • when current travels through a ground path other then the neutral
  • when the circuit is overloaded
  • when there is a short circuit
  • all of the above

Question 29

Question
a natural cooling process produced by moisture on the skin changing to low pressure steam is called _______.
Answer
  • conduction
  • convection
  • evaporation
  • radiation

Question 30

Question
during the heat season, human comfort can be enhanced without changing the temperature of the air by _________.
Answer
  • adding moisture
  • reducing moisture
  • increasing air filtration
  • increasing air speed

Question 31

Question
during the cooling season, dampers on bypass humidifiers should be ___________.
Answer
  • completely closed
  • completely open
  • set to 25% open
  • set to 50% open

Question 32

Question
all matter can exist as _________
Answer
  • liquid
  • gas
  • solid
  • all of the above

Question 33

Question
stored energy is called ____________ energy
Answer
  • controlled
  • kinetic
  • potential
  • quantum

Question 34

Question
heat that you can feel and measure directly with a thermometer is called ___________ heat.
Answer
  • absolute
  • latent
  • sensible
  • super

Question 35

Question
the heat energy change associated with a phase (state) change is called ________.
Answer
  • absolute
  • latent
  • sensible
  • super

Question 36

Question
the amount of heat (BTU) needed to raise the temperature of 1lb of a substance 1 degree is call the ___________ heat of the substance.
Answer
  • absolute
  • latent
  • sensible
  • specific

Question 37

Question
the latent heat of infusion is the amount of energy required to change 1 lb of a substance from ________ phase to the ________ phase without changing its temperature.
Answer
  • liquid, vapor
  • liquid, solid
  • solid, vapor
  • vapor, liquid

Question 38

Question
at 32F, 1lb of ice can changed to 1lb of water by adding _____ BTU.
Answer
  • 32
  • 44
  • 144
  • 970

Question 39

Question
at 212F 1lb of ice can be changed to 1 lb of steam by adding ______ Btu.
Answer
  • 32
  • 44
  • 144
  • 970

Question 40

Question
when liquid and vapor phases of a substance exist together, and no more liquid can vaporize without more energy being added, the vapor is said to be _______.
Answer
  • saturated
  • stabilized
  • subcooled
  • superheated

Question 41

Question
when a vapor is heated to a temperature higher than its saturation point, both the added heat and the temperature above saturation are called _________.
Answer
  • latent heat
  • sensible heat
  • specific heat
  • super heat

Question 42

Question
the process of molecules escaping from the surface of a liquid is called ________.
Answer
  • condensation
  • evaporation
  • saturation
  • subcooling

Question 43

Question
the process of a solid turning directly into a vapor without going through the liquid state is called _______.
Answer
  • saturation
  • subcooling
  • sublimation
  • superheating

Question 44

Question
the continuous movement of molecules within a liquid or gas is called ______ energy.
Answer
  • atomic
  • kinetic
  • potential
  • stored

Question 45

Question
enthalpy includes both _________ and ________ heat energy.
Answer
  • latent, sensible
  • latent, specific
  • sensible, specific
  • specific, absolute

Question 46

Question
the measurement of force that gravity exerts is called?
Answer
  • mass
  • specific matter
  • volume
  • weight

Question 47

Question
the amount of matter in a substance is called
Answer
  • gravity
  • mass
  • volume
  • weight

Question 48

Question
weight per unit of volume or mass per unit of volume is called?
Answer
  • density
  • specific gravity
  • specific mass
  • specific volume

Question 49

Question
volume per unit of mass or weight is called?
Answer
  • specific volume
  • specific mass
  • specific gravity
  • density

Question 50

Question
under standard conditions, air weights approximately _______ lb/ft3
Answer
  • 0.055
  • 0.065
  • 0.075
  • 0.085

Question 51

Question
solve to find the fahrenheit temperature corresponding to 30 celcius .
Answer
  • 32
  • 68
  • 70
  • 86

Question 52

Question
solve to find the fahrenheit temperature corresponding to 20 celcius
Answer
  • 32
  • 68
  • 70
  • 86

Question 53

Question
solve to find celsius temperature corresponding to 80 F
Answer
  • -1.1
  • 0
  • 15.6
  • 26.7

Question 54

Question
solve to find the Celsius temperature corresponding to 60
Answer
  • -1.1
  • 0
  • 15.6
  • 26.7

Question 55

Question
if the absolute temperature of a gas is doubled, under constant pressure the volume will be _______.
Answer
  • cut in half
  • doubled
  • increased by 25%
  • unchanged

Question 56

Question
what is the new volume of 1 ft3 of air at 0f when heated to 100f
Image:
Volume (binary/octet-stream)
Answer
  • 1
  • 1.2
  • 2
  • 3

Question 57

Question
if gauge pressure reads 30 psi, what is the corresponding absolute pressure?
Answer
  • 15.7
  • 34.7
  • 44.7
  • 60.7

Question 58

Question
the law that applies to the total pressure exerted by a mixture of gases or vapors is called __________ law.
Answer
  • boyles
  • charles
  • daltons
  • newtons
  • daves

Question 59

Question
an ampere is a measurement of what?
Answer
  • electrical charge
  • electron flow rate
  • opposition to current
  • potential energy

Question 60

Question
voltage is best defined as the ______?
Answer
  • amount of power being used in a circuit
  • force that moves electrons through a circuit
  • magnetic field surrounding a conductor
  • resistance to the flow of electrons

Question 61

Question
current in a circuit is limited by ______ ?
Answer
  • heat
  • resistance
  • temperature
  • voltage

Question 62

Question
a substance that permits the free movement of electrons is called a(n) ____________.
Answer
  • conductor
  • insulator
  • resistor
  • semiconductor

Question 63

Question
which of the following conductors would have the least resistance?
Answer
  • a long, large diameter conductor
  • a long, small diameter conductor
  • a short, large diameter conductor
  • a short, small diameter conductor

Question 64

Question
if the voltage in a circuit is doubled and the resistance remains the same, the current will _________.
Answer
  • drop to zero
  • be cut in half
  • double
  • stay the same

Question 65

Question
what is the voltage of a circuit if the resistance is 5 ohms and the current is 5 A?
Answer
  • 1 V
  • 2.5 V
  • 10 V
  • 25 V

Question 66

Question
A circuit has a voltage of 10 V and a current of 5 A. what is the resistances
Answer
  • 2
  • 15
  • 20
  • 50
  • Ohms sign looks like that, in equations it represented by R for resistance. this not an answer
    Image:
    Ohm (binary/octet-stream)

Question 67

Question
the total resistance of a series circuit is equal to the _________.
Answer
  • sum of all the resistances in the circuit
  • first resistance only
  • last resistance only
  • average of all the resistances

Question 68

Question
the total current in a parallel circuit is _______.
Answer
  • measured and divided by the number circuit paths
  • measured only at the first circuit path
  • the sum of the currents through the individual paths
  • the total of the first and the last circuit paths

Question 69

Question
the rate of doing work is called?
Answer
  • amperage
  • electricity
  • power
  • voltage

Question 70

Question
one kilowatt is equal to?
Answer
  • 10 W
  • 100 W
  • 1,000 W
  • 10,000 W

Question 71

Question
which of the following equations is used to solve for electric power
Answer
  • P = E x I
  • P = I2 x R
  • P = E2 / R
  • All of the above

Question 72

Question
what is the power in a circuit that has a current of 10 A and a resistance of 10 ohms
Answer
  • 1 kW
  • 10 kW
  • 100 kW
  • not enough information to solve

Question 73

Question
The voltage induced in each turn of the secondary coil of a transformer is __________?
Answer
  • half the voltage induced per turn of the primary coil
  • twice the voltage induced per turn of the primary coil
  • the same as the voltage induced per turn of the primary coil
  • determined by the ratio of turns in the primary to turns in the secondary

Question 74

Question
the load rating of a transformer is stated in ________.
Answer
  • amperes
  • volts
  • volt-amperes
  • watts

Question 75

Question
an ac induction motor consists of a stationary part called the _______ and a rotating part called the ________.
Answer
  • field, armature
  • primary winding, secondary winding
  • start winding, run winding
  • stator, rotor

Question 76

Question
what is the synchronous speed of a three-phase motor that has six poles and is operated on 60-Hz alternating current?
Answer
  • 1200 rpm
  • 3600 rpm
  • 4320 rpm
  • 7200 rpm

Question 77

Question
how does the power factor of an inductive motor affect efficiency?
Answer
  • the lower the power factor, the less efficient the motor is
  • the lower the power factor, the more efficient the motor is
  • the higher the power factor, the less efficient the motor is
  • the power factor has no effect on efficiency of the motor

Question 78

Question
which of the following single-phase ac motors does not have a start winding?
Answer
  • capacitor-start, capacitor-run
  • permanent split-capacitor
  • shaded-pole
  • split-phase

Question 79

Question
a centrifugal switch open the start winding circuit when a capacitor-start motor reaches approximately __________ % of its full speed.
Answer
  • 50%
  • 60 - 70 %
  • 75 - 80 %
  • 90 - 100 %

Question 80

Question
a run capacitor is always connected to the ________ and __________ terminals.
Answer
  • primary, secondary
  • run , common
  • start, common
  • start, run

Question 81

Question
terminal No.1 on all potential relays is always connected to the __________.
Answer
  • common terminal
  • run terminal
  • start capacitor
  • start terminal

Question 82

Question
the coil of a voltage relay is between terminal _________ and terminal ________ of the relay
Answer
  • 1, 5
  • 1, 2
  • 2, 5
  • 3, 5

Question 83

Question
what type of ac motor has the highest starting torque and the greatest efficiency?
Answer
  • capacitor-start, capacitor run
  • permanent split-capacitor
  • split-phase
  • three-phase

Question 84

Question
how many terminals does a dual-voltage three phase motor have?
Answer
  • 3
  • 6
  • 9
  • 12

Question 85

Question
the primary function of a wiring diagram is to ________.
Answer
  • aid the technician in finding the problem
  • help the owner repair the problem
  • provide the location of the components
  • reduce repair time

Question 86

Question
how many functions is an individual circuit in a control system designed to control
Answer
  • 1
  • 2
  • 3
  • unlimited

Question 87

Question
the five basic components common to all schematics are a power supply, a path, a load, a legend, and a ___________?
Answer
  • contactor
  • relay
  • switch
  • thermostat

Question 88

Question
the intention of the overall schematic is to show how the circuit _________.
Answer
  • components are connected
  • fails
  • functions
  • looks

Question 89

Question
the type of schematic that provides the most helpful troubleshooting information for the service technician is the __________ diagram.
Answer
  • connection
  • installation
  • ladder
  • pictorial

Question 90

Question
devices that consume power and convert it to some other form of energy, such as motion or heat are ____________.
Answer
  • contacts
  • fuses
  • loads
  • transformers

Question 91

Question
the normal dividing line for voltage changes in a schematic is the _________.
Answer
  • contactor
  • fuse
  • relay
  • transformer

Question 92

Question
the part of a schematic that lists and explains the system components is called the _________.
Answer
  • appendex
  • guide
  • index
  • legend

Question 93

Question
This symbol shown below represents a?
Image:
Symbol (binary/octet-stream)
Answer
  • double-pole, double-throw switch
  • double-pole, single-throw switch
  • single-pole, double-throw switch
  • single- pole, single-throw switch

Question 94

Question
see picture
Image:
Symbol 2 (binary/octet-stream)
Answer
  • a
  • b
  • c
  • d

Question 95

Question
relays and contactors are ___________ control switches.
Answer
  • electrically operated
  • manually operated
  • pressure- activated
  • temperature- activated

Question 96

Question
a(n) _________ circuit allows the same current to flow through all of the components.
Answer
  • ac
  • dc
  • parallel
  • series

Question 97

Question
a(n) _______________ circuit has multiple paths for current flow.
Answer
  • ac
  • dc
  • parallel
  • series

Question 98

Question
what type of circuits are primarily used in control and safety applications?
Answer
  • continuous
  • parallel
  • series
  • series-parallel

Question 99

Question
when testing with a voltmeter, you should place the meter __________.
Answer
  • in series with the circuit being tested
  • in parallel
  • on the highest possible setting
  • on the lowest possible setting

Question 100

Question
what does a resistance reading of 0 ohms indicate.
Answer
  • the circuit is open
  • the meter needs a new battery
  • the meter needs to be recalibrated
  • there is a short circuit

Question 101

Question
when you use an ohm meter, the circuit being measured must be _________.
Answer
  • energized
  • in use
  • isolated from all energy sources
  • at least 1.5 volts

Question 102

Question
when you test a switch with an ohm meter, a reading of ________ indicates that the switch is closed
Answer
  • 0 ohms
  • 24 V
  • 120 V
  • infinity

Question 103

Question
on all meters, digital and analog, the scale used should indicate the measurement ___________
Answer
  • close to the bottom of the range
  • close to the middle of the range
  • close to the top of the range
  • anywhere within the range

Question 104

Question
when testing across a closed switch in an energized circuit, you should read __________.
Answer
  • 0 ohms
  • infinite resistance
  • 0 V ac
  • 120 V ac

Question 105

Question
when using a standard clamp-on ammeter, you should ________ before taking a reading.
Answer
  • disconnect all of the wires in the circuit being tested
  • make sure that the jaws are closed
  • make sure that the jaws are open
  • shut down and lockout the equipment being tested

Question 106

Question
when testing compressor windings, you take the following readings: C to R: 2 ohms C to S: infinite resistance R to S: infinite resistance whats is the diagnosis?
Answer
  • the compressor is good
  • the run winding is shorted
  • the start winding is shorted
  • the start winding is open

Question 107

Question
capacitance meters must be used on capacitors _________.
Answer
  • connected in series
  • connected in parallel
  • in live circuits
  • that have been removed from the circuit

Question 108

Question
when testing a thermostat wire that has been removed from a circuit, you measure 0 ohms between red and white. this indicates that ______________.
Answer
  • the transformer is bad
  • the wiring is good
  • there is high resistance in the wire
  • there is a short

Question 109

Question
when testing with an ammeter, you should place the meter _____________.
Answer
  • in series with the circuit being tested
  • in parallel with the circuit being tested
  • on the highest possible setting
  • on the lowest possible setting
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