14347873
Descripción
Test por David Brown, actualizado hace más de 1 año
|
Creado por David Brown
hace casi 6 años
|
|
Pregunta 1
Pregunta
What is the volume of a room that measures 10ft by 20ft with an 8ft ceiling
Respuesta
-
800
-
1600
-
2400
-
3200
Pregunta 2
Pregunta
What is the CFM requirement for a 1800 ft2 house with 8 ft ceilings, if five air changes per hour are needed?
Respuesta
-
400
-
1200
-
1600
-
2400
Pregunta 3
Pregunta
what is them CFM requirement for an 2400 ft2 house with 8 ft ceilings, if five air changes per hour are needed.
Respuesta
-
400
-
1200
-
1600
-
2400
Pregunta 4
Pregunta
what is the cross sectional area of a 10-in round metal duct
Respuesta
-
79 in2
-
200 in2
-
314 in2
-
418 in2
Pregunta 5
Pregunta
how fast does air with a velocity pressure of 0.20in. w.g. move through a round duct
Respuesta
-
400ft/min
-
1200ft/min
-
1600ft/min
-
1800ft/min
Pregunta 6
Pregunta
how fast does air with a velocity pressure of 0.20in w.g. move through a square duct?
Respuesta
-
400 ft/min
-
1200 ft/min
-
1600 ft/min
-
1800 ft/min
Pregunta 7
Pregunta
What is the advantage of using a tube cutter to cut copper pipe?
Respuesta
-
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
Pregunta 8
Pregunta
spring-type benders may be used on ________?
Respuesta
-
soft drawn copper
-
hard copper
-
all copper pipe
-
steel pipe
Pregunta 9
Pregunta
a flaring tool is used to _________.
Respuesta
-
make a mechanical joint in tubing
-
measure pipe diameters
-
remove burrs from piping
-
separate pipe fittings
Pregunta 10
Pregunta
a swaging tool is used to _________.
Respuesta
-
cut copper pipe
-
make a mechanical joint in tubing
-
remove burrs from piping
-
solder tubing without the use of couplings
Pregunta 11
Pregunta
what is one of the advantages of a glass-stem thermometer?
Respuesta
-
it is very accurate
-
it is very durable
-
it comes with a digital readout
-
all of the above
-
none of the above
Pregunta 12
Pregunta
in discussing human comfort, the temperature most commonly referred to is __________.
Respuesta
-
dew point
-
dry-bulb
-
wet-bulb
-
fahrenheit
Pregunta 13
Pregunta
a sling psychrometer uses two glass-stem thermometers. one measures dry-bulb, and the other measures ______.
Respuesta
-
dew point
-
enthalpy
-
relative humidity
-
wet-bulb
Pregunta 14
Pregunta
a standard refrigeration manifold uses what type of element to measure pressure?
Respuesta
-
bellows
-
bourdon tube
-
diaphragm
-
spring
Pregunta 15
Pregunta
what is the pressure range of a standard compound gauge on a refrigeration manifold?
Respuesta
-
0 to 350 psi
-
0 to 500 psi
-
30in. Hg to 350 psi
-
30in. Hg to 500 psi
Pregunta 16
Pregunta
what is the best tool for removing moisture and noncondensibles from a system before adding refrigerant
Respuesta
-
manifold gauge
-
micron analyzer
-
recovery machine
-
vacuum pump
Pregunta 17
Pregunta
a vacuum gauge reads pressure in ______.
Respuesta
-
inches of mercury
-
inches of water
-
microns
-
psia
-
psig
Pregunta 18
Pregunta
which of the following is NOT a method of leak detection?
Respuesta
-
soap bubbles
-
electronic
-
micronic
-
ultrasonic
Pregunta 19
Pregunta
to prevent the release of refrigerant into the atmosphere, while removing it from a system what tool is used?
Respuesta
-
recovery machine
-
recycling machine
-
reclaim machine
-
vacuum pump
Pregunta 20
Pregunta
an anemometer uses a small fan blade to measure ______?
Respuesta
-
air pressure
-
air velocity
-
air volume
-
static pressure
Pregunta 21
Pregunta
what is one of the advantages using silver rods for brazing copper?
Respuesta
-
a lower melting temperature is required
-
a propane torch is used
-
no flux is required
-
no nitrogen purge is needed
Pregunta 22
Pregunta
what agency regulates cylinders and chemicals transported in a service vehicle?
Respuesta
-
ASHRAE
-
DOT
-
EPA
-
OSHA
-
ICE
-
DMV
-
LOL
-
YOLO
Pregunta 23
Pregunta
What is the maximum safe storage temperature of a refrigerant cylinder filled to 80% capacity by weight?
Respuesta
-
120 F
-
125 F
-
130 F
-
135 F
Pregunta 24
Pregunta
which of the following classification of fire extinguishers should be used for an electrical fire?
Respuesta
-
a
-
b
-
c
-
d
Pregunta 25
Pregunta
which of the following categories could be considered a hazardous atmosphere in a confined space?
Respuesta
-
asphyxiation
-
flammable
-
toxic
-
all of the above
Pregunta 26
Pregunta
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?
Respuesta
-
3 ft
-
4 ft
-
5 ft
-
6 ft
Pregunta 27
Pregunta
what is one of the most important safety precautions that you can take when working on electrical equipment
Respuesta
-
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
Pregunta 28
Pregunta
when does a ground fault circuit interrupter open an electric circuit?
Respuesta
-
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
Pregunta 29
Pregunta
a natural cooling process produced by moisture on the skin changing to low pressure steam is called _______.
Respuesta
-
conduction
-
convection
-
evaporation
-
radiation
Pregunta 30
Pregunta
during the heat season, human comfort can be enhanced without changing the temperature of the air by _________.
Respuesta
-
adding moisture
-
reducing moisture
-
increasing air filtration
-
increasing air speed
Pregunta 31
Pregunta
during the cooling season, dampers on bypass humidifiers should be ___________.
Respuesta
-
completely closed
-
completely open
-
set to 25% open
-
set to 50% open
Pregunta 32
Pregunta
all matter can exist as _________
Respuesta
-
liquid
-
gas
-
solid
-
all of the above
Pregunta 33
Pregunta
stored energy is called ____________ energy
Respuesta
-
controlled
-
kinetic
-
potential
-
quantum
Pregunta 34
Pregunta
heat that you can feel and measure directly with a thermometer is called ___________ heat.
Respuesta
-
absolute
-
latent
-
sensible
-
super
Pregunta 35
Pregunta
the heat energy change associated with a phase (state) change is called ________.
Respuesta
-
absolute
-
latent
-
sensible
-
super
Pregunta 36
Pregunta
the amount of heat (BTU) needed to raise the temperature of 1lb of a substance 1 degree is call the ___________ heat of the substance.
Respuesta
-
absolute
-
latent
-
sensible
-
specific
Pregunta 37
Pregunta
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.
Respuesta
-
liquid, vapor
-
liquid, solid
-
solid, vapor
-
vapor, liquid
Pregunta 38
Pregunta
at 32F, 1lb of ice can changed to 1lb of water by adding _____ BTU.
Respuesta
-
32
-
44
-
144
-
970
Pregunta 39
Pregunta
at 212F 1lb of ice can be changed to 1 lb of steam by adding ______ Btu.
Respuesta
-
32
-
44
-
144
-
970
Pregunta 40
Pregunta
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 _______.
Respuesta
-
saturated
-
stabilized
-
subcooled
-
superheated
Pregunta 41
Pregunta
when a vapor is heated to a temperature higher than its saturation point, both the added heat and the temperature above saturation are called _________.
Respuesta
-
latent heat
-
sensible heat
-
specific heat
-
super heat
Pregunta 42
Pregunta
the process of molecules escaping from the surface of a liquid is called ________.
Respuesta
-
condensation
-
evaporation
-
saturation
-
subcooling
Pregunta 43
Pregunta
the process of a solid turning directly into a vapor without going through the liquid state is called _______.
Respuesta
-
saturation
-
subcooling
-
sublimation
-
superheating
Pregunta 44
Pregunta
the continuous movement of molecules within a liquid or gas is called ______ energy.
Respuesta
-
atomic
-
kinetic
-
potential
-
stored
Pregunta 45
Pregunta
enthalpy includes both _________ and ________ heat energy.
Respuesta
-
latent, sensible
-
latent, specific
-
sensible, specific
-
specific, absolute
Pregunta 46
Pregunta
the measurement of force that gravity exerts is called?
Respuesta
-
mass
-
specific matter
-
volume
-
weight
Pregunta 47
Pregunta
the amount of matter in a substance is called
Respuesta
-
gravity
-
mass
-
volume
-
weight
Pregunta 48
Pregunta
weight per unit of volume or mass per unit of volume is called?
Respuesta
-
density
-
specific gravity
-
specific mass
-
specific volume
Pregunta 49
Pregunta
volume per unit of mass or weight is called?
Respuesta
-
specific volume
-
specific mass
-
specific gravity
-
density
Pregunta 50
Pregunta
under standard conditions, air weights approximately _______ lb/ft3
Respuesta
-
0.055
-
0.065
-
0.075
-
0.085
Pregunta 51
Pregunta
solve to find the fahrenheit temperature corresponding to 30 celcius .
Respuesta
-
32
-
68
-
70
-
86
Pregunta 52
Pregunta
solve to find the fahrenheit temperature corresponding to 20 celcius
Respuesta
-
32
-
68
-
70
-
86
Pregunta 53
Pregunta
solve to find celsius temperature corresponding to 80 F
Respuesta
-
-1.1
-
0
-
15.6
-
26.7
Pregunta 54
Pregunta
solve to find the Celsius temperature corresponding to 60
Respuesta
-
-1.1
-
0
-
15.6
-
26.7
Pregunta 55
Pregunta
if the absolute temperature of a gas is doubled, under constant pressure the volume will be _______.
Respuesta
-
cut in half
-
doubled
-
increased by 25%
-
unchanged
Pregunta 56
Pregunta
what is the new volume of 1 ft3 of air at 0f when heated to 100f
Image:
Volume (binary/octet-stream)
Respuesta
-
1
-
1.2
-
2
-
3
Pregunta 57
Pregunta
if gauge pressure reads 30 psi, what is the corresponding absolute pressure?
Respuesta
-
15.7
-
34.7
-
44.7
-
60.7
Pregunta 58
Pregunta
the law that applies to the total pressure exerted by a mixture of gases or vapors is called __________ law.
Respuesta
-
boyles
-
charles
-
daltons
-
newtons
-
daves
Pregunta 59
Pregunta
an ampere is a measurement of what?
Respuesta
-
electrical charge
-
electron flow rate
-
opposition to current
-
potential energy
Pregunta 60
Pregunta
voltage is best defined as the ______?
Respuesta
-
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
Pregunta 61
Pregunta
current in a circuit is limited by ______ ?
Respuesta
-
heat
-
resistance
-
temperature
-
voltage
Pregunta 62
Pregunta
a substance that permits the free movement of electrons is called a(n) ____________.
Respuesta
-
conductor
-
insulator
-
resistor
-
semiconductor
Pregunta 63
Pregunta
which of the following conductors would have the least resistance?
Respuesta
-
a long, large diameter conductor
-
a long, small diameter conductor
-
a short, large diameter conductor
-
a short, small diameter conductor
Pregunta 64
Pregunta
if the voltage in a circuit is doubled and the resistance remains the same, the current will _________.
Respuesta
-
drop to zero
-
be cut in half
-
double
-
stay the same
Pregunta 65
Pregunta
what is the voltage of a circuit if the resistance is 5 ohms and the current is 5 A?
Respuesta
-
1 V
-
2.5 V
-
10 V
-
25 V
Pregunta 66
Pregunta
A circuit has a voltage of 10 V and a current of 5 A. what is the resistances
Respuesta
-
2
-
15
-
20
-
50
-
Ohms sign looks like that, in equations it represented by R for resistance. this not an answerImage:Ohm (binary/octet-stream)
Pregunta 67
Pregunta
the total resistance of a series circuit is equal to the _________.
Respuesta
-
sum of all the resistances in the circuit
-
first resistance only
-
last resistance only
-
average of all the resistances
Pregunta 68
Pregunta
the total current in a parallel circuit is _______.
Respuesta
-
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
Pregunta 69
Pregunta
the rate of doing work is called?
Respuesta
-
amperage
-
electricity
-
power
-
voltage
Pregunta 70
Pregunta
one kilowatt is equal to?
Respuesta
-
10 W
-
100 W
-
1,000 W
-
10,000 W
Pregunta 71
Pregunta
which of the following equations is used to solve for electric power
Respuesta
-
P = E x I
-
P = I2 x R
-
P = E2 / R
-
All of the above
Pregunta 72
Pregunta
what is the power in a circuit that has a current of 10 A and a resistance of 10 ohms
Respuesta
-
1 kW
-
10 kW
-
100 kW
-
not enough information to solve
Pregunta 73
Pregunta
The voltage induced in each turn of the secondary coil of a transformer is __________?
Respuesta
-
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
Pregunta 74
Pregunta
the load rating of a transformer is stated in ________.
Respuesta
-
amperes
-
volts
-
volt-amperes
-
watts
Pregunta 75
Pregunta
an ac induction motor consists of a stationary part called the _______ and a rotating part called the ________.
Respuesta
-
field, armature
-
primary winding, secondary winding
-
start winding, run winding
-
stator, rotor
Pregunta 76
Pregunta
what is the synchronous speed of a three-phase motor that has six poles and is operated on 60-Hz alternating current?
Respuesta
-
1200 rpm
-
3600 rpm
-
4320 rpm
-
7200 rpm
Pregunta 77
Pregunta
how does the power factor of an inductive motor affect efficiency?
Respuesta
-
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
Pregunta 78
Pregunta
which of the following single-phase ac motors does not have a start winding?
Respuesta
-
capacitor-start, capacitor-run
-
permanent split-capacitor
-
shaded-pole
-
split-phase
Pregunta 79
Pregunta
a centrifugal switch open the start winding circuit when a capacitor-start motor reaches approximately __________ % of its full speed.
Respuesta
-
50%
-
60 - 70 %
-
75 - 80 %
-
90 - 100 %
Pregunta 80
Pregunta
a run capacitor is always connected to the ________ and __________ terminals.
Respuesta
-
primary, secondary
-
run , common
-
start, common
-
start, run
Pregunta 81
Pregunta
terminal No.1 on all potential relays is always connected to the __________.
Respuesta
-
common terminal
-
run terminal
-
start capacitor
-
start terminal
Pregunta 82
Pregunta
the coil of a voltage relay is between terminal _________ and terminal ________ of the relay
Respuesta
-
1, 5
-
1, 2
-
2, 5
-
3, 5
Pregunta 83
Pregunta
what type of ac motor has the highest starting torque and the greatest efficiency?
Respuesta
-
capacitor-start, capacitor run
-
permanent split-capacitor
-
split-phase
-
three-phase
Pregunta 84
Pregunta
how many terminals does a dual-voltage three phase motor have?
Respuesta
-
3
-
6
-
9
-
12
Pregunta 85
Pregunta
the primary function of a wiring diagram is to ________.
Respuesta
-
aid the technician in finding the problem
-
help the owner repair the problem
-
provide the location of the components
-
reduce repair time
Pregunta 86
Pregunta
how many functions is an individual circuit in a control system designed to control
Respuesta
-
1
-
2
-
3
-
unlimited
Pregunta 87
Pregunta
the five basic components common to all schematics are a power supply, a path, a load, a legend, and a ___________?
Respuesta
-
contactor
-
relay
-
switch
-
thermostat
Pregunta 88
Pregunta
the intention of the overall schematic is to show how the circuit _________.
Respuesta
-
components are connected
-
fails
-
functions
-
looks
Pregunta 89
Pregunta
the type of schematic that provides the most helpful troubleshooting information for the service technician is the __________ diagram.
Respuesta
-
connection
-
installation
-
ladder
-
pictorial
Pregunta 90
Pregunta
devices that consume power and convert it to some other form of energy, such as motion or heat are ____________.
Respuesta
-
contacts
-
fuses
-
loads
-
transformers
Pregunta 91
Pregunta
the normal dividing line for voltage changes in a schematic is the _________.
Respuesta
-
contactor
-
fuse
-
relay
-
transformer
Pregunta 92
Pregunta
the part of a schematic that lists and explains the system components is called the _________.
Respuesta
-
appendex
-
guide
-
index
-
legend
Pregunta 93
Respuesta
-
double-pole, double-throw switch
-
double-pole, single-throw switch
-
single-pole, double-throw switch
-
single- pole, single-throw switch
Pregunta 94
Respuesta
-
a
-
b
-
c
-
d
Pregunta 95
Pregunta
relays and contactors are ___________ control switches.
Respuesta
-
electrically operated
-
manually operated
-
pressure- activated
-
temperature- activated
Pregunta 96
Pregunta
a(n) _________ circuit allows the same current to flow through all of the components.
Respuesta
-
ac
-
dc
-
parallel
-
series
Pregunta 97
Pregunta
a(n) _______________ circuit has multiple paths for current flow.
Respuesta
-
ac
-
dc
-
parallel
-
series
Pregunta 98
Pregunta
what type of circuits are primarily used in control and safety applications?
Respuesta
-
continuous
-
parallel
-
series
-
series-parallel
Pregunta 99
Pregunta
when testing with a voltmeter, you should place the meter __________.
Respuesta
-
in series with the circuit being tested
-
in parallel
-
on the highest possible setting
-
on the lowest possible setting
Pregunta 100
Pregunta
what does a resistance reading of 0 ohms indicate.
Respuesta
-
the circuit is open
-
the meter needs a new battery
-
the meter needs to be recalibrated
-
there is a short circuit
Pregunta 101
Pregunta
when you use an ohm meter, the circuit being measured must be _________.
Respuesta
-
energized
-
in use
-
isolated from all energy sources
-
at least 1.5 volts
Pregunta 102
Pregunta
when you test a switch with an ohm meter, a reading of ________ indicates that the switch is closed
Respuesta
-
0 ohms
-
24 V
-
120 V
-
infinity
Pregunta 103
Pregunta
on all meters, digital and analog, the scale used should indicate the measurement ___________
Respuesta
-
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
Pregunta 104
Pregunta
when testing across a closed switch in an energized circuit, you should read __________.
Respuesta
-
0 ohms
-
infinite resistance
-
0 V ac
-
120 V ac
Pregunta 105
Pregunta
when using a standard clamp-on ammeter, you should ________ before taking a reading.
Respuesta
-
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
Pregunta 106
Pregunta
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?
Respuesta
-
the compressor is good
-
the run winding is shorted
-
the start winding is shorted
-
the start winding is open
Pregunta 107
Pregunta
capacitance meters must be used on capacitors _________.
Respuesta
-
connected in series
-
connected in parallel
-
in live circuits
-
that have been removed from the circuit
Pregunta 108
Pregunta
when testing a thermostat wire that has been removed from a circuit, you measure 0 ohms between red and white. this indicates that ______________.
Respuesta
-
the transformer is bad
-
the wiring is good
-
there is high resistance in the wire
-
there is a short
Pregunta 109
Pregunta
when testing with an ammeter, you should place the meter _____________.
Respuesta
-
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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