Exam
Name___________________________________
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the
question.
1)
1)
What is the main component that makes a thermoelectric cooling system work?
A)
An absorber
B)
A wetted media
C)
A compressor
D)
A thermocouple
Answer:
D
A)
B)
C)
D)
2)
2)
What occurs when gas is squeezed into a smaller space?
A)
The pressure and temperature lower.
B)
The pressure rises and temperature lowers.
C)
The pressure lowers and temperature rises.
D)
The pressure and temperature rise.
Answer:
D
A)
B)
C)
D)
3)
3)
The four types of cooling mechanisms are:
A)
Absorption, adaptive compression, conductive, resistive.
B)
Mechanical compression, electrical compression, adaptive expansion, thermoelectric.
C)
Evaporative, conductive, resistive, mechanical.
D)
Evaporative, thermoelectric, absorption, mechanical compression.
Answer:
D
A)
B)
C)
D)
1
4)
4)
What components in a compression–refrigeration system maintain the pressure difference in the
system?
A)
The metering device and evaporator
B)
The compressor and the metering device
C)
The condenser and evaporator
D)
The compressor and condenser
Answer:
B
A)
B)
C)
D)
5)
5)
When a liquid boils:
A)
Its temperature remains the same as it boils.
B)
Its temperature increases as it boils.
C)
Its temperature drops as it boils.
D)
The temperature of a liquid is not related to its boiling point.
Answer:
A
A)
B)
C)
D)
6)
6)
A refrigeration system that uses the Peltier effect is called:
A)
An electrolytic refrigeration system.
B)
An absorption refrigeration system.
C)
A compression refrigeration system.
D)
A thermoelectric refrigeration system.
Answer:
D
A)
B)
C)
D)
7)
7)
Which of the following systems uses compression pumps and condensers to cool the air?
A)
Mechanical compression system
B)
Thermoelectric system
C)
Absorption system
D)
Evaporative system
Answer:
A
A)
B)
C)
D)
2
8)
8)
What does a refrigeration system do with the heat in the refrigerated area?
A)
It moves the heat from the refrigerated area to another area.
B)
It chemically absorbs the heat.
C)
Nothing–refrigeration is about cold, not heat.
D)
It overcomes the heat with a counterbalancing quantity of cold.
Answer:
A
A)
B)
C)
D)
9)
9)
The temperature of a boiling liquid:
A)
Is set by the chemical properties of the liquid and does not change.
B)
Is controlled by the rate that heat is applied to the boiling liquid.
C)
Is controlled by the pressure on the liquid.
D)
Is set by the physical properties of the liquid and does not change.
Answer:
C
A)
B)
C)
D)
10)
10)
What is the purpose of the wetted media in an evaporative cooling system?
A)
Water evaporates from the wetted media, reducing the air temperature.
B)
Ammonia is moved across the wetted media.
C)
Water is moved across the wetted media to pretreat the air.
D)
Water is absorbed by the wetted media to increase air temperature.
Answer:
A
A)
B)
C)
D)
11)
11)
The four major components of the compression–refrigeration cycle in order are:
A)
Compressor, condenser, metering device, evaporator.
B)
Metering device, condenser, evaporator, compressor.
C)
Condenser metering device compressor, evaporator.
D)
Compressor, evaporator, condenser, metering device.
Answer:
A
A)
B)
C)
D)
3
12)
12)
At what point in the refrigeration cycle does the refrigerant absorb the most heat?
A)
In the compressor where it changes from a low–temperature gas to a high–temperature gas
B)
At the end of the evaporator where the gas is superheated
C)
In the middle of the evaporator where the cold liquid turns to a cold gas
D)
In the condenser where it changes from a gas to a liquid
Answer:
C
A)
B)
C)
D)
13)
13)
Why does the compression–refrigeration cycle have a high–pressure side and a low–pressure
side?
A)
So the refrigerant can condense at a low pressure and temperature and evaporate at a high
pressure and temperature
B)
The pressure difference is not intentionally created, but is simply the result of circulating
refrigerant with the compressor.
C)
So the refrigerant can evaporate at a low pressure and temperature and condense at a high
pressure and temperature
D)
The pressure difference is the result of polar molecular alignment due to the intense
magnetic field created by the compressor motor.
Answer:
C
A)
B)
C)
D)
14)
14)
What does the absorption cycle use to create the system pressure difference needed to produce the
cooling effect?
A)
The absorption cycle uses pressure and heat.
B)
The absorption cycle uses heat.
C)
The absorption cycle uses heat and an absorbent fluid.
D)
The absorption cycle uses pressure and an absorbent fluid.
Answer:
C
A)
B)
C)
D)
4
15)
15)
Which of the following do modern thermoelectric modules use to create the Peltier effect?
A)
Wires
B)
Semiconductors
C)
Compressors
D)
Water
Answer:
B
A)
B)
C)
D)
16)
16)
Refrigeration can be defined as:
A)
Moving heat from where it is not wanted to where it is unobjectionable.
B)
Pumping in cold through the use of refrigerant.
C)
Adding cold to an area or substance.
D)
Chemically accelerating the molecular counterrotation.
Answer:
A
A)
B)
C)
D)
17)
17)
Which of the following remains constant during condensation?
A)
B)
C)
D)
Answer:
D
A)
B)
C)
D)
18)
18)
Which of the four types of refrigeration systems cools the air without removing any heat from the
air?
A)
Thermoelectric systems
B)
Absorption refrigeration systems
C)
Mechanical refrigeration systems
D)
Evaporative systems
Answer:
D
A)
B)
C)
D)
5
19)
19)
Which of the following did Thomas Seebeck discover regarding electrical flow?
A)
Small amounts of electrical current flow through the wires if two junction points are at
different temperatures.
B)
Large amounts of electrical current flow through the wires if two junction points are at
different temperatures.
C)
Small amounts of electrical current flow through the wires if two junction points are at the
same temperature.
D)
No electrical current flows through the wires if two junction points are at different
temperatures.
Answer:
A
A)
B)
C)
D)
20)
20)
Which of the following would have the greatest effect on the heat content of refrigerant?
A)
The refrigerant’s temperature
B)
The refrigerant’s humidity
C)
The refrigerant’s pressure
D)
The refrigerant‘s state
Answer:
D
A)
B)
C)
D)
21)
21)
Evaporative cooling systems work by:
A)
Evaporating HFC refrigerants into the air, which reduces the temperature.
B)
Evaporating refrigerant inside a component called an evaporator.
C)
Evaporating the heat out of the air which makes the heat disappear.
D)
Evaporating water, which reduces the temperature of the air.
Answer:
D
A)
B)
C)
D)
22)
22)
What components are found on both the compression cycle and the absorption cycle?
A)
Compressor and absorber
B)
Evaporator and condenser
C)
Compressor and condenser
D)
Generator and absorber
Answer:
B
A)
B)
C)
D)
6
23)
23)
Evaporative cooling is very effective:
A)
In any climate.
B)
In areas of high humidity like the southeastern United States.
C)
In coastal areas with high humidity.
D)
In areas of low humidity like the southwestern United States.
Answer:
D
A)
B)
C)
D)
24)
24)
A mechanical refrigeration system cools a room by:
A)
Realigning the air molecules in the room.
B)
Radiating cold energy into the room.
C)
Adding cold to the room until the level of cold reaches the proper level.
D)
Removing heat from the room.
Answer:
D
A)
B)
C)
D)
25)
25)
What components maintain the high and low pressures in an absorption refrigeration system?
A)
The condenser, evaporator, and absorber
B)
The absorber, metering device, and evaporator
C)
The generator, the absorber, and the solution pump
D)
The metering device, evaporator, and generator
Answer:
C
A)
B)
C)
D)
26)
26)
How can the effectiveness of evaporative cooling be increased?
A)
By mixing product and working air
B)
By using multiple stages
C)
By using warmer air
D)
By adding humidity
Answer:
B
A)
B)
C)
D)
7
27)
27)
How does a boiling liquid affect the heat of its container?
A)
Heat flows out of the liquid and into its container, adding heat to the container.
B)
The boiling liquid converts the container’s specific heat into sensible heat.
C)
The boiling liquid has no effect on the heat of its container.
D)
Heat flows out of the container into the liquid, removing heat from the container.
Answer:
D
A)
B)
C)
D)
28)
28)
Which statement accurately describes heat flow between two objects?
A)
Heat travels from the object with the lower temperature to the object with the higher
temperature.
B)
Heat travels from the object with the higher temperature to the object with the lower
temperature.
C)
Heat travels from the object with the higher BTU quantity to the object with the lower BTU
quantity.
D)
Heat travels from the object with the lower BTU quantity to the object with the higher BTU
quantity.
Answer:
B
A)
B)
C)
D)
29)
29)
At what point in the refrigeration cycle does the refrigerant lose the most heat?
A)
In the middle of the condenser where it changes from a gas to a liquid
B)
In the metering device where it goes in as a warm liquid and leaves as a cold, saturated
mixture
C)
In the end of the condenser where the liquid is subcooled
D)
In the middle of the evaporator where the cold liquid turns to a cold gas
Answer:
A
A)
B)
C)
D)
8
30)
30)
Which of the following occurs in the condenser during the compression cycle?
A)
The refrigerant changes from a gas to a liquid.
B)
The refrigerant boils to a gas.
C)
The water vapor condenses.
D)
The water vapor boils to a gas.
Answer:
A
A)
B)
C)
D)
31)
31)
Where is subcooled refrigerant found?
A)
Where the refrigerant changes from liquid to gas
B)
Where the refrigerant changes from gas to liquid
C)
Where the refrigerant is a gas
D)
Where the refrigerant is a liquid
Answer:
D
A)
B)
C)
D)
32)
32)
A forced–draft air–cooled condenser:
A)
Uses a fan to suck air across the condenser coil.
B)
Does not use a fan, relying on natural convection.
C)
Uses magnetic induction instead of a fan to create air movement.
D)
Uses a fan to blow air across the condenser coil.
Answer:
D
A)
B)
C)
D)
33)
33)
The most efficient operation is achieved with:
A)
Automatic expansion valves.
B)
Thermostatic expansion valves.
C)
Capillary tubes.
D)
Orifice–type metering devices.
Answer:
B
A)
B)
C)
D)
9
34)
34)
The four major components of the compression refrigeration cycle in order are:
A)
Compressor, condenser, metering device, evaporator.
B)
Condenser metering device compressor, evaporator.
C)
Compressor, evaporator, condenser, metering device.
D)
Metering device, condenser, evaporator, compressor.
Answer:
A
A)
B)
C)
D)
35)
35)
A compressor that uses a high–speed impeller to throw the refrigerant outwards is called a:
A)
Screw compressor.
B)
Reciprocating compressor.
C)
Rotary compressor.
D)
Centrifugal compressor.
Answer:
D
A)
B)
C)
D)
36)
36)
The two large classes of metering devices are:
A)
Hand valves and automatic valves.
B)
Fixed restrictions and thermostatic expansion valves.
C)
Floats and valves.
D)
Fixed restrictions and broken restrictions.
Answer:
B
A)
B)
C)
D)
37)
37)
A compressor that squeezes gas between two rotating screws shaped like augers is called a:
A)
Rotary compressor.
B)
Reciprocating compressor.
C)
Scroll compressor.
D)
Screw compressor.
Answer:
D
A)
B)
C)
D)
10
38)
38)
The refrigeration cycle is made possible by the ________ difference, which is maintained by the
compressor and metering device.
A)
B)
C)
D)
Answer:
D
A)
B)
C)
D)
39)
39)
Compared to the condenser coils in older systems, the condenser coils in new higher–efficiency
systems:
A)
Are made of larger–bore tubing to improve refrigerant flow.
B)
Have fewer fins per inch to allow for better air flow.
C)
Are physically larger than older lower–efficiency coils.
D)
Are physically smaller because of their improved efficiency.
Answer:
C
A)
B)
C)
D)
40)
40)
The line that connects the condenser to the metering device is called the:
A)
Suction line.
B)
Discharge line.
C)
Liquid line.
D)
Condensate line.
Answer:
C
A)
B)
C)
D)
41)
41)
The small line on a split system air–conditioning unit is the:
A)
B)
C)
D)
Answer:
B
A)
B)
C)
D)
11
42)
42)
At what point in the refrigeration cycle does the refrigerant lose the most heat?
A)
In the middle of the evaporator where the cold liquid turns to a cold gas
B)
In the end of the condenser where the liquid is subcooled
C)
In the metering device where it goes in as a warm liquid and leaves as a cold saturated
mixture
D)
In the middle of the condenser where it changes from a gas to a liquid
Answer:
D
A)
B)
C)
D)
43)
43)
On an R–410A air conditioning system, the refrigerant leaving the ________ is 118 psig, 50°F, 100
percent superheated gas.
A)
metering device
B)
evaporator
C)
condenser
D)
compressor
Answer:
B
A)
B)
C)
D)
44)
44)
The line that connects the evaporator to the compressor is called the:
A)
Suction line.
B)
Discharge line.
C)
Liquid line.
D)
Condensate line.
Answer:
A
A)
B)
C)
D)
45)
45)
Which of the two refrigerant lines going to the compressor is larger?
A)
The high–pressure discharge line
B)
The low–pressure suction line
C)
The low–pressure discharge line
D)
The high–pressure suction line
Answer:
B
A)
B)
C)
D)
12
46)
46)
The refrigerant leaves the ________ as a low–pressure, low–temperature, superheated vapor and
returns to the compressor.
A)
evaporator
B)
condenser
C)
compressor
D)
expansion device
Answer:
A
A)
B)
C)
D)
47)
47)
In the compression refrigeration cycle, the refrigerant is saturated:
A)
In the evaporator and condenser.
B)
Only in the metering device.
C)
In the compressor and condenser.
D)
Only in the compressor.
Answer:
A
A)
B)
C)
D)
48)
48)
Which component of the refrigeration cycle controls the flow of refrigerant to the evaporator? It
also separates the high– and low–pressure sides of the system.
A)
Metering device
B)
Evaporator
C)
Compressor
D)
Condenser
Answer:
A
A)
B)
C)
D)
49)
49)
The refrigerant is a high–pressure, warm, subcooled liquid at the inlet of the metering device. The
state of the refrigerant is:
A)
95 percent liquid.
B)
100 percent liquid.
C)
75 percent liquid.
D)
50 percent liquid.
Answer:
B
A)
B)
C)
D)
13
50)
50)
The line that connects the compressor to the condenser is called the:
A)
Suction line.
B)
Discharge line.
C)
Liquid line.
D)
Condensate line.
Answer:
B
A)
B)
C)
D)
51)
51)
The two refrigerant lines connecting the inside and outside units of a split system air conditioner
are:
A)
Suction line and liquid line.
B)
The discharge line and suction line.
C)
The liquid line and condensate line.
D)
The discharge line and liquid line.
Answer:
A
A)
B)
C)
D)
52)
52)
At what point in the refrigeration cycle does the refrigerant absorb the most heat?
A)
At the end of the evaporator where the gas is superheated
B)
In the condenser where it changes from a gas to a liquid
C)
In the compressor where it changes from a low–temperature gas to a high–temperature gas
D)
In the middle of the evaporator where the cold liquid turns to a cold gas
Answer:
D
A)
B)
C)
D)
53)
53)
Where is the liquid receiver located?
A)
On the high side just after the compressor
B)
On the low side just before the compressor
C)
On the low side just after the metering device
D)
On the high side just after the condenser
Answer:
D
A)
B)
C)
D)
14
54)
54)
Why does the compression refrigeration cycle have a high–pressure side?
A)
To allow the refrigerant to boil
B)
So the refrigerant can evaporate at a high pressure and temperature
C)
To save on the amount of refrigerant required at lower pressures
D)
So the refrigerant can condense at a high pressure and temperature
Answer:
D
A)
B)
C)
D)
55)
55)
A compressor that uses a roller that rotates in an orbital motion to squeeze gas between the roller
and a spring–loaded vane is called a:
A)
Rotary compressor.
B)
Reciprocating compressor.
C)
Scroll compressor.
D)
Screw compressor.
Answer:
A
A)
B)
C)
D)
56)
56)
A compressor that squeezes gas between the piston and a valve plate at the top of the cylinder is
called a:
A)
Rotary compressor.
B)
Reciprocating compressor.
C)
Scroll compressor.
D)
Screw compressor.
Answer:
B
A)
B)
C)
D)
57)
57)
The temperature of the liquid refrigerant is reduced as heat continues to be expelled to the
surrounding air. This portion of the condenser is called the ________ section.
A)
B)
C)
D)
Answer:
C
A)
B)
C)
D)
15
58)
58)
Optional components on the high side of a refrigeration system include:
A)
Discharge line muffler, oil separator, liquid receiver, and liquid line filter–drier.
B)
Suction to liquid heat exchanger, economizer, and oil level regulator.
C)
Suction line filter, accumulator, and evaporator pressure regulator.
D)
All optional components can be used on the high side of the system.
Answer:
A
A)
B)
C)
D)
59)
59)
The order of the four main components of the refrigeration cycle is:
A)
Condenser – compressor – metering device – evaporator.
B)
Compressor – condenser – metering device – evaporator.
C)
Evaporator –condenser – metering device – compressor.
D)
Compressor – evaporator – condenser – metering device.
Answer:
B
A)
B)
C)
D)
60)
60)
What happens to the refrigerant on the low–pressure side of a compression cycle refrigeration
system?
A)
The refrigerant expels heat while evaporating.
B)
The refrigerant condenses at a low pressure and temperature.
C)
The refrigerant evaporates at a low pressure and temperature.
D)
The refrigerant expels heat while condensing.
Answer:
C
A)
B)
C)
D)
61)
61)
________ ensures that no liquid slugs will reach the compressor and cause damage to the valves
and pistons. The state of the refrigerant is 100% gas.
A)
B)
C)
D)
Answer:
D
A)
B)
C)
D)
16
62)
62)
The discharge, liquid, and suction lines of a packaged unit are:
A)
Located inside the unit.
B)
Located on top of the unit.
C)
Located outside the unit.
D)
Not necessary.
Answer:
A
A)
B)
C)
D)
63)
63)
In the compression refrigeration cycle, the refrigerant is superheated:
A)
The refrigerant is not superheated anywhere in the compression cycle.
B)
The refrigerant contains some superheat throughout the cycle.
C)
Leaving the compressor, through the condenser, up to the metering device.
D)
Leaving the evaporator, through the compressor, up to the condenser.
Answer:
D
A)
B)
C)
D)
64)
64)
The difference between a liquid receiver and a suction accumulator is that:
A)
An accumulator is located on the high side just before the condenser.
B)
Receivers receive the refrigerant that accumulators accumulate.
C)
Receivers only allow liquid to leave while accumulators only allow vapor to leave.
D)
A liquid receiver is used after the evaporator on the high side.
Answer:
C
A)
B)
C)
D)
65)
65)
What components in a compression refrigeration system maintain the pressure difference in the
system?
A)
The compressor and the metering device
B)
The condenser and evaporator
C)
The compressor and condenser
D)
The metering device and evaporator
Answer:
A
A)
B)
C)
D)
17
66)
66)
In the compression refrigeration cycle, the refrigerant is subcooled:
A)
Leaving the evaporator up to the compressor.
B)
The refrigerant is not superheated anywhere in the compression cycle.
C)
Leaving the condenser up to the metering device.
D)
Leaving the metering device, through the evaporator, up to the compressor.
Answer:
C
A)
B)
C)
D)
67)
67)
An induced–draft air–cooled condenser:
A)
Does not use a fan, relying on natural convection.
B)
Uses a fan to suck air across the condenser coil.
C)
Uses magnetic induction to create air movement instead of a fan.
D)
Uses a fan to blow air across the condenser coil.
Answer:
B
A)
B)
C)
D)
68)
68)
Where is the suction accumulator located?
A)
On the high side just after the compressor
B)
On the low side just before the compressor
C)
On the low side just after the metering device
D)
On the high side just after the condenser
Answer:
B
A)
B)
C)
D)
18
69)
69)
Assuming they both have the same condenser temperature, which application requires more
horsepower to produce a ton of cooling: a 0°F evaporator, or a 40°F evaporator?
A)
The horsepower requirement is too complicated a calculation to make any valid comparison
based only on evaporator and condenser temperatures.
B)
The 40°F evaporator, because of its higher pressure
C)
The 0°F evaporator, because of the higher pressure difference
D)
The horsepower requirement per ton of cooling is not affected by the evaporator
temperature.
Answer:
C
A)
B)
C)
D)
70)
70)
Which of the following has the capacity range for a centrifugal compressor?
A)
Commercial AC
B)
Appliance
C)
Residential AC
D)
Refrigeration
Answer:
A
A)
B)
C)
D)
71)
71)
A compressor that uses an impeller to throw refrigerant from the center outward is a:
A)
Centrifugal compressor.
B)
Rotary compressor.
C)
Screw compressor.
D)
Scroll compressor.
Answer:
A
A)
B)
C)
D)
72)
72)
A compressor that uses an offset rolling piston that seals against a blade that remains stationary
and moves in and out of its slot to seal against the rolling piston is a:
A)
Rotary blade rotary compressor.
B)
Rotary screw compressor.
C)
Reciprocating compressor.
D)
Stationary blade rotary compressor.
Answer:
D
A)
B)
C)
D)
19
73)
73)
How can hermetic compressors be characterized?
A)
They have a bolted housing that encloses both the compressor and motor.
B)
They have a shaft that connects to an external motor.
C)
They have a welded shell with a shaft that connects to an external motor.
D)
They have a welded shell, which holds both the compressor and motor.
Answer:
D
A)
B)
C)
D)
74)
74)
Which of the following is TRUE of a medium–temperature refrigeration unit?
A)
It requires 1 hp to produce 2/3 ton of cooling.
B)
It requires 1 hp to produce 1–1/3 tons of cooling.
C)
It requires 1 hp to produce 1/3 ton of cooling.
D)
It requires 1 hp to produce 1 ton of cooling.
Answer:
A
A)
B)
C)
D)
75)
75)
The small gaps between the screws on the screw compressor are sealed by:
A)
Oil flooding.
B)
The malleable metal the screws are made of.
C)
Rings on the end of the rotors.
D)
Tip seals.
Answer:
A
A)
B)
C)
D)
76)
76)
An oil slinger is used with reciprocating compressors that are lubricated by:
A)
Both splash and pressure lubrication.
B)
Pressure lubrication.
C)
Splash lubrication.
D)
Oil slingers are used only with scroll compressors.
Answer:
C
A)
B)
C)
D)
20