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38 Cards in this Set
- Front
- Back
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What is the purpose of a reduced voltage starter?
A. increase motor torque B. reduce inrush current C. vary the motors speed D. allow multiple motor voltage |
B. reduce inrush current
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Which of the following id not a reduced voltage starter?
A.autotransmitter B. star-delta C. primary resistor D. solid state |
A.autotransmitter
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How many btu's are required to change one pound of ice at 20°F to steam at 220°F?
A. 1,304 Btu/h B. 2,608 Btu/h C. 6,520 Btu/h D. 3,912 Btu/h |
A. 1,304 Btu/h
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How many Btu's must be removed from one pound of water at 200°F for it to end up as ice at 30°F
A. 144 Btu B. 828 Btu C. 313 Btu D. 526 Btu |
C. 313 Btu
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How many Btu's are required to change five pounds of ice at 20°F to steam at 220°F?
A. 1,304 Btu/h B. 2,608 Btu/h C. 6,520 Btu/h D. 3,912 Btu/h |
C. 6,520 Btu/h
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Pure water boils at a temperature of 212°F at which of the following standard conditions?
A. 12.967 B. 13.697 C. 14.696 D. 15.967 |
C. 14.696
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The temperature on the Fahrenheit scale where all molecular biology activity stops is _____ .
A. -450°F B. -460°F C. -0°F D. -462.95°F |
B. -460°F
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The Celsius equivalent of 80°F is _____ .
A. 25.5°C B. 26.7°C C. 26.3°C D. 27.5°C |
B. 26.7°C
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PSIG indicates ____ .
A. pounds per square inch absolute gravity B. pounds per square inch absolute gage C. pounds per square inch of pressure absolute D. pounds per square inch of gravity |
B. pounds per square inch absolute gage
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A Bourdon tube is often found in a _____ .
A. mercury barometer B. aneroid barometer C. pressure gauge D. mercury thermometer |
C. pressure gauge
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A liquid material exerts a pressure of force _____ .
A. in all directions B. downward only C. outward and downward D. outward only |
C. outward and downward
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Refrigeration can be described as _____ .
A. the process of making products cold B. the process of introducing heat to a location where it is not wanted C. the process of removing heat from a place where it is not wanted to a place where it makes little or no difference D. none of the above |
C. the process of removing heat from a place where it is not wanted to a place where it makes little or no difference
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The pressure in a refrigeration system is chaned in the ____ .
A. condenser and compressor B. compressor and expansion device C. expansion device and evaporator D. condenser and evaporator |
D. condenser and evaporator
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At what location or locations in a refrigeration system does the saturation pressure correspond to the saturation temperature?
A. compressor and evaporator B. evaporator and condenser C. condenser and expansion device D. compressor |
B. evaporator and condenser
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Ice melts in a icebox because ____ .
A. Heat flows through the insulated walls B. Heat enters when the door is opened C. Heat enters when warm food is placed in the icebox D. All of the above |
D. All of the above
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High temperature refrigeration is that produced by ____ .
A. heat from a furnace B. an air-conditioning system C. the vegetable cooling system of a refrigerator D. the freezer section of a refrigerator |
B. an air-conditioning system
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The evaporator in a refrigeration system ____ .
A. reduces the boiling point of the refrigerant B. condenses the refrigerant C. absorbs heat from the product to be cooled D. compresses the refrigerant vapor |
C. absorbs heat from the product to be cooled
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The law requires technicians to recover refrigerant from all refrigeration systems so that they ____ .
A. will not be released into the atmosphere B. may be used again C. may be reclaimed for future use D. all of the above |
D. all of the above
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When it is necessary to perform electrical work in an area that has a damp or wet floor, which of the following can be done to minimize the chance of electrical shock?
A. Place a rubber mat on te floor. B. Use a wooden ladder. C. Wear insulated boots and gloves. D. All of the above. |
D. All of the above.
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An example of a pressure vessel is ____ .
A. a small ship containing refrigerant cylinders B. the compressor in a refrigeration unit C. a cylinder containing refrigerant D. a portable dolly |
C. a cylinder containing refrigerant
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A fusible plug is a metal fitting that has a hole drilled through it and the hole is filled with ____ .
A. material with a low melting point B. plastic C. copper fused with brass D. a metal alloy that will burn when overheated |
A. material with a low melting point
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Before using a voltmeter, always ____ .
A. Zero the ohms adjustment B. Touch the two leads together to insure continuity C. Set the range selector to a setting higher than te voltage you expect to read D. Turn off the power |
C. Set the range selector to a setting higher than te voltage you expect to read
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A double insulated drill ___ .
A. has two ground wires to insure proper grounding B. generally has a plastic case with the electrical connections and motor insulated within the tool C. is used with a three-to two-prong adaptor D. has rechargeable batteries |
B. generally has a plastic case with the electrical connections and motor insulated within the tool
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Air conditioning and refrigeration reversible ratchet wrenches are used to ___ .
A. tighten hex head sheet metal screws B. tighten flare nuts C. open and close refrigerant service valves D. tighten nuts that cannot be reached with other wrenches |
C. open and close refrigerant service valves
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Flare nut wrenches are used to ____ .
A. tighten or loosen nuts on copper tubing B. open or close refrigerant service valves C. tighten nuts that cannot be reached with other wrenches D. remove hex head screws from refrigerator cabinets |
A. tighten or loosen nuts on copper tubing
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A sling psychrometer ____ .
A. measures the dry-bulb and wet-bulb temperatures of air B. measures the air velocity through a duct C. uses a microprocessor to provide information for proper air balance D. measures the quantity of air, in cfm, flowing through a duct |
A. measures the dry-bulb and wet-bulb temperatures of air
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For fastening two pieces of rough lumber together, the nail used would be a ____ .
A. finishing nail B. common nail C. roofing nail D. masonry nail |
B. common nail
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To fasten a duct hanger strap to a floor joist, the nail used would be a ____ .
A. finishing nail B. common nail C. roofing nail D. masonry nail |
C. roofing nail
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If a technician needed a 5/8" ACR for an installation and was located near only a plumbing supply house, what size and type of pipe should he ask for?
A. 5/8" ACR B. 1/2" PVC C. 1/2" ID type L copper D. 5/8" PVC |
C. 1/2" ID type L copper
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The size indicated for the diameter of ACR copper tubing is the approximate ___ .
A. inside diameter B. outside diameter C. wall thickness D. none of the above |
B. outside diameter
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The maximum temperature at which soft soldering is done is ____ .
A. 400°F B. 212°F C. 600°F D. 800°F |
D. 800°F
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When soldering or brazing, the solder is ____ .
A. heated directly by the flame of the heat source B. heated by the surrounding air C. used to oxidize the metal D. melted by heat from the tubing and fitting |
D. melted by heat from the tubing and fitting
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Pipe threads, when used on pipe that will contain liquid or vapor pressure, ____ .
A. are tapered B. should have at least seven perfect threads C. generally have a "V" shape D. all of the above |
D. all of the above
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The proper type of flame from an oxy-acetylene torch for silver brazing is _____ .
A. long tail flame B. neutral flame C. oxidizing flame D. carbonizing flame |
B. neutral flame
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A compound gauge ______ .
A. indicates pressures above 14.696 psia. B. indicates pressures at sea level C. is one of two gauges on a typical gauge manifold D. all of the above |
C. is one of two gauges on a typical gauge manifold
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A micron gauge is used to measure ____ .
A. atmospheric pressures at high altitudes B. atmospheric pressures at sea level C. absolute pressure below 1 mm Hg D. high pressure in a refrigeration system |
C. absolute pressure below 1 mm Hg.
(1mm Hg. = 1000 Microns) |
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the best method of leak checking is when the refrigeration system is ____ .
A. in a vacuum B. open to the atmosphere C. operating with all fans activated D. standing with dry nitrogen pressure of 150 psig in the system |
D. standing with dry nitrogen pressure of 150 psig in the system
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Noncondensible gases ____ .
A. are deesirable in a refrigeration system B. are undesirable in a refrigeration system C. condense readily under normal atmospheric conditions D. help in pulling a vacuum |
B. are undesirable in a refrigeration system
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