Frage 1
Frage
What is the volume of a room that measures 10ft by 20ft with an 8ft ceiling
Frage 2
Frage
What is the CFM requirement for a 1800 ft2 house with 8 ft ceilings, if five air changes per hour are needed?
Frage 3
Frage
what is them CFM requirement for an 2400 ft2 house with 8 ft ceilings, if five air changes per hour are needed.
Frage 4
Frage
what is the cross sectional area of a 10-in round metal duct
Antworten
-
79 in2
-
200 in2
-
314 in2
-
418 in2
Frage 5
Frage
how fast does air with a velocity pressure of 0.20in. w.g. move through a round duct
Antworten
-
400ft/min
-
1200ft/min
-
1600ft/min
-
1800ft/min
Frage 6
Frage
how fast does air with a velocity pressure of 0.20in w.g. move through a square duct?
Antworten
-
400 ft/min
-
1200 ft/min
-
1600 ft/min
-
1800 ft/min
Frage 7
Frage
What is the advantage of using a tube cutter to cut copper pipe?
Antworten
-
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
Frage 8
Frage
spring-type benders may be used on ________?
Antworten
-
soft drawn copper
-
hard copper
-
all copper pipe
-
steel pipe
Frage 9
Frage
a flaring tool is used to _________.
Frage 10
Frage
a swaging tool is used to _________.
Frage 11
Frage
what is one of the advantages of a glass-stem thermometer?
Frage 12
Frage
in discussing human comfort, the temperature most commonly referred to is __________.
Antworten
-
dew point
-
dry-bulb
-
wet-bulb
-
fahrenheit
Frage 13
Frage
a sling psychrometer uses two glass-stem thermometers. one measures dry-bulb, and the other measures ______.
Antworten
-
dew point
-
enthalpy
-
relative humidity
-
wet-bulb
Frage 14
Frage
a standard refrigeration manifold uses what type of element to measure pressure?
Antworten
-
bellows
-
bourdon tube
-
diaphragm
-
spring
Frage 15
Frage
what is the pressure range of a standard compound gauge on a refrigeration manifold?
Antworten
-
0 to 350 psi
-
0 to 500 psi
-
30in. Hg to 350 psi
-
30in. Hg to 500 psi
Frage 16
Frage
what is the best tool for removing moisture and noncondensibles from a system before adding refrigerant
Antworten
-
manifold gauge
-
micron analyzer
-
recovery machine
-
vacuum pump
Frage 17
Frage
a vacuum gauge reads pressure in ______.
Antworten
-
inches of mercury
-
inches of water
-
microns
-
psia
-
psig
Frage 18
Frage
which of the following is NOT a method of leak detection?
Antworten
-
soap bubbles
-
electronic
-
micronic
-
ultrasonic
Frage 19
Frage
to prevent the release of refrigerant into the atmosphere, while removing it from a system what tool is used?
Antworten
-
recovery machine
-
recycling machine
-
reclaim machine
-
vacuum pump
Frage 20
Frage
an anemometer uses a small fan blade to measure ______?
Antworten
-
air pressure
-
air velocity
-
air volume
-
static pressure
Frage 21
Frage
what is one of the advantages using silver rods for brazing copper?
Frage 22
Frage
what agency regulates cylinders and chemicals transported in a service vehicle?
Antworten
-
ASHRAE
-
DOT
-
EPA
-
OSHA
-
ICE
-
DMV
-
LOL
-
YOLO
Frage 23
Frage
What is the maximum safe storage temperature of a refrigerant cylinder filled to 80% capacity by weight?
Frage 24
Frage
which of the following classification of fire extinguishers should be used for an electrical fire?
Frage 25
Frage
which of the following categories could be considered a hazardous atmosphere in a confined space?
Antworten
-
asphyxiation
-
flammable
-
toxic
-
all of the above
Frage 26
Frage
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?
Frage 27
Frage
what is one of the most important safety precautions that you can take when working on electrical equipment
Antworten
-
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
Frage 28
Frage
when does a ground fault circuit interrupter open an electric circuit?
Antworten
-
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
Frage 29
Frage
a natural cooling process produced by moisture on the skin changing to low pressure steam is called _______.
Antworten
-
conduction
-
convection
-
evaporation
-
radiation
Frage 30
Frage
during the heat season, human comfort can be enhanced without changing the temperature of the air by _________.
Frage 31
Frage
during the cooling season, dampers on bypass humidifiers should be ___________.
Antworten
-
completely closed
-
completely open
-
set to 25% open
-
set to 50% open
Frage 32
Frage
all matter can exist as _________
Antworten
-
liquid
-
gas
-
solid
-
all of the above
Frage 33
Frage
stored energy is called ____________ energy
Antworten
-
controlled
-
kinetic
-
potential
-
quantum
Frage 34
Frage
heat that you can feel and measure directly with a thermometer is called ___________ heat.
Antworten
-
absolute
-
latent
-
sensible
-
super
Frage 35
Frage
the heat energy change associated with a phase (state) change is called ________.
Antworten
-
absolute
-
latent
-
sensible
-
super
Frage 36
Frage
the amount of heat (BTU) needed to raise the temperature of 1lb of a substance 1 degree is call the ___________ heat of the substance.
Antworten
-
absolute
-
latent
-
sensible
-
specific
Frage 37
Frage
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.
Antworten
-
liquid, vapor
-
liquid, solid
-
solid, vapor
-
vapor, liquid
Frage 38
Frage
at 32F, 1lb of ice can changed to 1lb of water by adding _____ BTU.
Frage 39
Frage
at 212F 1lb of ice can be changed to 1 lb of steam by adding ______ Btu.
Frage 40
Frage
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 _______.
Antworten
-
saturated
-
stabilized
-
subcooled
-
superheated
Frage 41
Frage
when a vapor is heated to a temperature higher than its saturation point, both the added heat and the temperature above saturation are called _________.
Antworten
-
latent heat
-
sensible heat
-
specific heat
-
super heat
Frage 42
Frage
the process of molecules escaping from the surface of a liquid is called ________.
Antworten
-
condensation
-
evaporation
-
saturation
-
subcooling
Frage 43
Frage
the process of a solid turning directly into a vapor without going through the liquid state is called _______.
Antworten
-
saturation
-
subcooling
-
sublimation
-
superheating
Frage 44
Frage
the continuous movement of molecules within a liquid or gas is called ______ energy.
Antworten
-
atomic
-
kinetic
-
potential
-
stored
Frage 45
Frage
enthalpy includes both _________ and ________ heat energy.
Antworten
-
latent, sensible
-
latent, specific
-
sensible, specific
-
specific, absolute
Frage 46
Frage
the measurement of force that gravity exerts is called?
Antworten
-
mass
-
specific matter
-
volume
-
weight
Frage 47
Frage
the amount of matter in a substance is called
Antworten
-
gravity
-
mass
-
volume
-
weight
Frage 48
Frage
weight per unit of volume or mass per unit of volume is called?
Antworten
-
density
-
specific gravity
-
specific mass
-
specific volume
Frage 49
Frage
volume per unit of mass or weight is called?
Antworten
-
specific volume
-
specific mass
-
specific gravity
-
density
Frage 50
Frage
under standard conditions, air weights approximately _______ lb/ft3
Frage 51
Frage
solve to find the fahrenheit temperature corresponding to 30 celcius .
Frage 52
Frage
solve to find the fahrenheit temperature corresponding to 20 celcius
Frage 53
Frage
solve to find celsius temperature corresponding to 80 F
Frage 54
Frage
solve to find the Celsius temperature corresponding to 60
Frage 55
Frage
if the absolute temperature of a gas is doubled, under constant pressure the volume will be _______.
Antworten
-
cut in half
-
doubled
-
increased by 25%
-
unchanged
Frage 56
Frage
what is the new volume of 1 ft3 of air at 0f when heated to 100f
Frage 57
Frage
if gauge pressure reads 30 psi, what is the corresponding absolute pressure?
Frage 58
Frage
the law that applies to the total pressure exerted by a mixture of gases or vapors is called __________ law.
Antworten
-
boyles
-
charles
-
daltons
-
newtons
-
daves
Frage 59
Frage
an ampere is a measurement of what?
Antworten
-
electrical charge
-
electron flow rate
-
opposition to current
-
potential energy
Frage 60
Frage
voltage is best defined as the ______?
Antworten
-
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
Frage 61
Frage
current in a circuit is limited by ______ ?
Antworten
-
heat
-
resistance
-
temperature
-
voltage
Frage 62
Frage
a substance that permits the free movement of electrons is called a(n) ____________.
Antworten
-
conductor
-
insulator
-
resistor
-
semiconductor
Frage 63
Frage
which of the following conductors would have the least resistance?
Antworten
-
a long, large diameter conductor
-
a long, small diameter conductor
-
a short, large diameter conductor
-
a short, small diameter conductor
Frage 64
Frage
if the voltage in a circuit is doubled and the resistance remains the same, the current will _________.
Antworten
-
drop to zero
-
be cut in half
-
double
-
stay the same
Frage 65
Frage
what is the voltage of a circuit if the resistance is 5 ohms and the current is 5 A?
Frage 66
Frage
A circuit has a voltage of 10 V and a current of 5 A. what is the resistances
Frage 67
Frage
the total resistance of a series circuit is equal to the _________.
Frage 68
Frage
the total current in a parallel circuit is _______.
Antworten
-
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
Frage 69
Frage
the rate of doing work is called?
Antworten
-
amperage
-
electricity
-
power
-
voltage
Frage 70
Frage
one kilowatt is equal to?
Antworten
-
10 W
-
100 W
-
1,000 W
-
10,000 W
Frage 71
Frage
which of the following equations is used to solve for electric power
Antworten
-
P = E x I
-
P = I2 x R
-
P = E2 / R
-
All of the above
Frage 72
Frage
what is the power in a circuit that has a current of 10 A and a resistance of 10 ohms
Frage 73
Frage
The voltage induced in each turn of the secondary coil of a transformer is __________?
Antworten
-
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
Frage 74
Frage
the load rating of a transformer is stated in ________.
Antworten
-
amperes
-
volts
-
volt-amperes
-
watts
Frage 75
Frage
an ac induction motor consists of a stationary part called the _______ and a rotating part called the ________.
Antworten
-
field, armature
-
primary winding, secondary winding
-
start winding, run winding
-
stator, rotor
Frage 76
Frage
what is the synchronous speed of a three-phase motor that has six poles and is operated on 60-Hz alternating current?
Antworten
-
1200 rpm
-
3600 rpm
-
4320 rpm
-
7200 rpm
Frage 77
Frage
how does the power factor of an inductive motor affect efficiency?
Antworten
-
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
Frage 78
Frage
which of the following single-phase ac motors does not have a start winding?
Frage 79
Frage
a centrifugal switch open the start winding circuit when a capacitor-start motor reaches approximately __________ % of its full speed.
Antworten
-
50%
-
60 - 70 %
-
75 - 80 %
-
90 - 100 %
Frage 80
Frage
a run capacitor is always connected to the ________ and __________ terminals.
Antworten
-
primary, secondary
-
run , common
-
start, common
-
start, run
Frage 81
Frage
terminal No.1 on all potential relays is always connected to the __________.
Antworten
-
common terminal
-
run terminal
-
start capacitor
-
start terminal
Frage 82
Frage
the coil of a voltage relay is between terminal _________ and terminal ________ of the relay
Frage 83
Frage
what type of ac motor has the highest starting torque and the greatest efficiency?
Frage 84
Frage
how many terminals does a dual-voltage three phase motor have?
Frage 85
Frage
the primary function of a wiring diagram is to ________.
Antworten
-
aid the technician in finding the problem
-
help the owner repair the problem
-
provide the location of the components
-
reduce repair time
Frage 86
Frage
how many functions is an individual circuit in a control system designed to control
Frage 87
Frage
the five basic components common to all schematics are a power supply, a path, a load, a legend, and a ___________?
Antworten
-
contactor
-
relay
-
switch
-
thermostat
Frage 88
Frage
the intention of the overall schematic is to show how the circuit _________.
Antworten
-
components are connected
-
fails
-
functions
-
looks
Frage 89
Frage
the type of schematic that provides the most helpful troubleshooting information for the service technician is the __________ diagram.
Antworten
-
connection
-
installation
-
ladder
-
pictorial
Frage 90
Frage
devices that consume power and convert it to some other form of energy, such as motion or heat are ____________.
Antworten
-
contacts
-
fuses
-
loads
-
transformers
Frage 91
Frage
the normal dividing line for voltage changes in a schematic is the _________.
Antworten
-
contactor
-
fuse
-
relay
-
transformer
Frage 92
Frage
the part of a schematic that lists and explains the system components is called the _________.
Antworten
-
appendex
-
guide
-
index
-
legend
Frage 93
Frage
This symbol shown below represents a?
Antworten
-
double-pole, double-throw switch
-
double-pole, single-throw switch
-
single-pole, double-throw switch
-
single- pole, single-throw switch
Frage 94
Frage 95
Frage
relays and contactors are ___________ control switches.
Antworten
-
electrically operated
-
manually operated
-
pressure- activated
-
temperature- activated
Frage 96
Frage
a(n) _________ circuit allows the same current to flow through all of the components.
Frage 97
Frage
a(n) _______________ circuit has multiple paths for current flow.
Frage 98
Frage
what type of circuits are primarily used in control and safety applications?
Antworten
-
continuous
-
parallel
-
series
-
series-parallel
Frage 99
Frage
when testing with a voltmeter, you should place the meter __________.
Antworten
-
in series with the circuit being tested
-
in parallel
-
on the highest possible setting
-
on the lowest possible setting
Frage 100
Frage
what does a resistance reading of 0 ohms indicate.
Frage 101
Frage
when you use an ohm meter, the circuit being measured must be _________.
Frage 102
Frage
when you test a switch with an ohm meter, a reading of ________ indicates that the switch is closed
Antworten
-
0 ohms
-
24 V
-
120 V
-
infinity
Frage 103
Frage
on all meters, digital and analog, the scale used should indicate the measurement ___________
Antworten
-
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
Frage 104
Frage
when testing across a closed switch in an energized circuit, you should read __________.
Antworten
-
0 ohms
-
infinite resistance
-
0 V ac
-
120 V ac
Frage 105
Frage
when using a standard clamp-on ammeter, you should ________ before taking a reading.
Antworten
-
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
Frage 106
Frage
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?
Antworten
-
the compressor is good
-
the run winding is shorted
-
the start winding is shorted
-
the start winding is open
Frage 107
Frage
capacitance meters must be used on capacitors _________.
Frage 108
Frage
when testing a thermostat wire that has been removed from a circuit, you measure 0 ohms between red and white. this indicates that ______________.
Frage 109
Frage
when testing with an ammeter, you should place the meter _____________.
Antworten
-
in series with the circuit being tested
-
in parallel with the circuit being tested
-
on the highest possible setting
-
on the lowest possible setting