REFRIGERATION AND AIR CONDITIONING
1.Short cycling of a refrigeration compressor refers to _____________.
A.frequently grounding out
B.frequently starting and stopping
C.running too fast
D.running too slow
[bg_collapse view=”button-orange” color=”#49494a” expand_text=”View Answer” collapse_text=”Hide Answer” ]B.frequently starting and stopping[/bg_collapse]
2.The heat gained per pound of refrigerant in the evaporator is known as the _____________.
A.latent heat of vaporization
B.sensible heat
C.refrigerating effect
D.specific heat of vaporization
[bg_collapse view=”button-orange” color=”#49494a” expand_text=”View Answer” collapse_text=”Hide Answer” ]C.refrigerating effect[/bg_collapse]
3.When liquid reaches the compressor of a refrigeration system through the suction line, the condition is called _____________.
A.flooding back
B.superheating
C.overflowing
D.recycling
[bg_collapse view=”button-orange” color=”#49494a” expand_text=”View Answer” collapse_text=”Hide Answer” ]A.flooding back[/bg_collapse]
4.Which of the refrigerants listed is considered safe and ideal for most marine applications?
A.R-21
B.Ammonia
C.R-12
D.Sulfur dioxide
[bg_collapse view=”button-orange” color=”#49494a” expand_text=”View Answer” collapse_text=”Hide Answer” ]C.R-12[/bg_collapse]
5.The heat removed from the refrigerant in the condenser of a refrigeration plant is the _____________.
A.latent heat of expansion
B.sensible heat of condensation
C.heat of compression
D.all of the above
[bg_collapse view=”button-orange” color=”#49494a” expand_text=”View Answer” collapse_text=”Hide Answer” ]C.heat of compression[/bg_collapse]
6.The FIRST thing to do to ensure that a refrigeration unit will not start while undergoing repairs, is to ____________.
A.secure and tag the electrical circuit
B.place a crow bar in the flywheel of the unit
C.inform all persons in the area not to start the unit
D.make a log book entry
[bg_collapse view=”button-orange” color=”#49494a” expand_text=”View Answer” collapse_text=”Hide Answer” ]A.secure and tag the electrical circuit[/bg_collapse]
7.In a refrigeration system, the refrigerant absorbs the latent heat of vaporization in the _____________.
A.compressor
B.condenser
C.receiver
D.evaporator
[bg_collapse view=”button-orange” color=”#49494a” expand_text=”View Answer” collapse_text=”Hide Answer” ]D.evaporator[/bg_collapse]
8.Personnel working with refrigeration systems, and subject to the exposure of refgerants should wear ________________.
A.face shield
B.a respirator
C.rubber gloves
D.an all purpose gas mask
[bg_collapse view=”button-orange” color=”#49494a” expand_text=”View Answer” collapse_text=”Hide Answer” ]A.face shield[/bg_collapse]
9.The heat required to change a substance from a solid to a liquid while at its freezing temperature, is known as the latent heat of _____________.
A.fusion
B.vaporization
C.condensation
D.sublimation
[bg_collapse view=”button-orange” color=”#49494a” expand_text=”View Answer” collapse_text=”Hide Answer” ] A.fusion[/bg_collapse]
10.The only means of removing the latent heat of condensation from a refrigerant in the normal refrigeration cycle is by _________.
A.passing it through the expansion valve
B.condensing refrigerant in the system condenser
C.passing the gaseous refrigerant through the heat interchanger on the suction side of the compressor
D.maintaining a high pressure on the system’s receiver
[bg_collapse view=”button-orange” color=”#49494a” expand_text=”View Answer” collapse_text=”Hide Answer” ]B.condensing refrigerant in the system condenser[/bg_collapse]
11.The amount of moisture in a given sample of air, when compared with the amount of moisture the air could hold if totally saturated at the existing temperature of the sample, is called ____________.
A.absolute humidity
B.specific humidity
C.effective humidity
D.relative humidity
[bg_collapse view=”button-orange” color=”#49494a” expand_text=”View Answer” collapse_text=”Hide Answer” ]D.relative humidity[/bg_collapse]
12.When it is necessary to open a refrigeration system for repairs and the system will be open for more than a few minutes, the open ends of the system should be ____________.
A.dehydrated
B.purged
C.plugged
D.evacuated
[bg_collapse view=”button-orange” color=”#49494a” expand_text=”View Answer” collapse_text=”Hide Answer” ]C.plugged[/bg_collapse]
13.People familiar with ammonia refrigeration systems become accustomed to its odor and may forget that the vapors _____________.
A.in a low concentration can cause death
B.will dissolve in perspiration and cause caustic burns
C.will burn or explode
D.all of the above
[bg_collapse view=”button-orange” color=”#49494a” expand_text=”View Answer” collapse_text=”Hide Answer” ]D.all of the above[/bg_collapse]
14.When subjected to high heat from a open flame, or an electric heating element, which of the listed refrigerants will break down and produce phosgene gas?
A.CO2
B.Methyl chloride
C.R-22
D.Sulphur dioxide
[bg_collapse view=”button-orange” color=”#49494a” expand_text=”View Answer” collapse_text=”Hide Answer” ]C.R-22[/bg_collapse]
15.A refrigeration system contaminated with moisture can be affected by _____________.
A.acid formation
B.sludge formation
C.ice in the expansion valve
C.allowed to mix with compressor oil
[bg_collapse view=”button-orange” color=”#49494a” expand_text=”View Answer” collapse_text=”Hide Answer” ][/bg_collapse]
16.Some chloronated flourocarbon refrigerants may decompose into a toxic irritating gas if it is ____________.
A.stored at temperatures below 60 degrees Fahrenheit
B.charged into a system having copper fittings
D.all of the above
D.exposed to an open flame or hot surface
[bg_collapse view=”button-orange” color=”#49494a” expand_text=”View Answer” collapse_text=”Hide Answer” ]D.exposed to an open flame or hot surface[/bg_collapse]
17.In a direct expansion type cargo refrigeration system, a box is normally changed from chill to freeze by adjusting the _____________.
A.hand expansion valve
B.compressor suction valve
C.solenoid bypass
D.back pressure regulating valve
[bg_collapse view=”button-orange” color=”#49494a” expand_text=”View Answer” collapse_text=”Hide Answer” ]
D.back pressure regulating valve[/bg_collapse]
18.If the suction line between the evaporator and compressor is frosting up, the cause may be due to the thermal expansion valve _____________.
A.thermal bulb coming loose from the suction line
B.needle valve is stuck closed
C.thermal bulb is in a cold air stream
D.all of the above
[bg_collapse view=”button-orange” color=”#49494a” expand_text=”View Answer” collapse_text=”Hide Answer” ]A.thermal bulb coming loose from the suction line[/bg_collapse]
