WorksheetsME 433 - Q1E - P1
Total questions: 115
Worksheet time: 58mins
Name
Class
Date
1.
The boiling point of CO at atmospheric pressure is:
a)
-110°F
b)
+110°F
c)
-28°C
d)
-28°C
2.
The boiling point of NH3 at atmospheric pressure is:
a)
+28°C
b)
+28°F
c)
-28°C
d)
-28°F
3.
Which of the following would you apply if a person got Freon in his eyes?
a)
clean water
b)
soapy water
c)
sodium bicarbonate
d)
sterile mineral oil
4.
A double-seated valve allows the valve to be:
a)
packed only in the closed position
b)
packed in the wide open or closed position
c)
operated as a suction or discharge valve
d)
removed for replacement without shutting down
5.
The amount of CO<sub>2</sub> or Freon in a cylinder is measured by:
a)
pressure
b)
weight
c)
volume
d)
psi
6.
The latent heat of fusion of ice is:
a)
500 Btu
b)
188 Btu
c)
144 Btu
d)
970 Btu
7.
Latent heat:
a)
can be measured with a pyrometer
b)
cannot be measured with a thermometer
c)
changes as the refrigerant cools
d)
can be measured with a thermometer
8.
Absolute zero is:
a)
144° below zero on the fahrenheit scale
b)
The same as zero on the fahrenheit scale
c)
970° below zero on the fahrenheit scale
d)
460° below zero on the fahrenheit scale
9.
A ton of refrigeration is equal to the cooling effect of:
a)
2,000 lbs. of ice melting in 24 hrs
b)
2,000 lbs. of water being converted to ice
c)
2,000 lbs. of ice melting in 12 hrs
d)
2,240 lbs. of ice melting in 24 hrs
10.
What is another name of discharge pressure?
a)
Absolute pressure
b)
Head pressure
c)
Suction pressure
d)
Condenser pressure
11.
Which of the following is the oil used in a refrigeration system?
a)
Vegetable oil
b)
Straight mineral oil
c)
Lube oil SAE 20
d)
Lube oil SAE 10
12.
One disadvantage of a CO<sub>2</sub> system is the fact that:
a)
It is difficult to condense the refrigerant if the circulating water temperature is too high
b)
It takes more refrigerant to keep the iceboxes cold
c)
Due to high pressure it is difficult to keep oil from mixing with the refrigerant
d)
It is difficult to condense the refrigerant of the circulating water temperature is to low
13.
The disadvantage of a CO<sub>2</sub> system over an ammonia system is the fact that _____.
a)
The pipes and fittings is a CO<sub>2</sub> system must be of high-pressure type
b)
The CO<sub>2</sub> system operates at a much higher pressure
c)
The CO<sub>2</sub> system requires a larger prime mover
d)
All of these
14.
A good refrigerant should be:
a)
Non-inflammable
b)
Non-poisonous
c)
Non-explosive
d)
All of these
15.
What tonnage of refrigerating machine is required if the refrigerating system extracted 48,000 BTU per hour?
a)
2 tons
b)
5 tons
c)
4 tons
d)
3 tons
16.
What is the combination of a wet and dry bulb thermometer is called a:
a)
A. Hygrometer
b)
B. Psychrometer
c)
C. Hydrometer
d)
A or B
17.
A pressure controller is usually operated by the movement of a:
a)
A. Bellows
b)
B. Siphon
c)
C. Diaphragm
d)
A or C
18.
The critical temperature of a refrigerant is:
a)
The temperature at which it will freeze
b)
The temperature above which it cannot be liquefied
c)
The temperature below which it cannot be liquefied
d)
None of these
19.
If the critical temperature of a refrigerant is too close to the desired condensing temperature, the equipment must necessarily be of:
a)
Extra heavy construction
b)
The direct expansion type
c)
Light construction
d)
The indirect expansion type
20.
A good refrigerant should have a:
a)
High sensible heat
b)
low sensible heat
c)
High latent heat
d)
Latent heat
21.
Which of the following is the most common method of heat flow in refrigeration?
a)
Conduction
b)
Expulsion
c)
Radiation
d)
convection
22.
From which of the following processes where the largest quantities of heat are available?
a)
Vaporization
b)
Melting
c)
Fusion
d)
cooling
23.
What is the most common Freon gas used in centrifugal compressors?
a)
F-12
b)
F-11
c)
F-22
d)
F-21
24.
What is the most common Freon gas used in reciprocating compressors?
a)
F-12
b)
F-11
c)
F-22
d)
F-21
25.
The temperature in the meat and fish box should be approximately:
a)
10° to 20°F
b)
-10° to 0°F
c)
0° to -10°F
d)
-10° to 10°F
26.
The temperature in the vegetable box should be approximately:
a)
35° to 45°F
b)
10° to 20°F
c)
40° to 50°F
d)
15° to 30°F
27.
The temperature in the diary box should be approximately:
a)
20° to 30°F
b)
0° to 20°F
c)
10° to 20°F
d)
30° to 40°F
28.
Which of the following can be the cause of low head pressure?
a)
Too much or too cold condensing water
b)
Leaky discharge valves
c)
Insufficient charge of refrigerant
d)
Any of these
29.
In thermostatic expansion valves did not appear to be functioning properly, the cause could be:
a)
Foreign matter in the valve
b)
Ruptured control bulb tubing
c)
Moisture in the system
d)
Any of these
30.
Which of the following is used in measuring the density of a brine solution?
a)
A. Litmus paper
b)
B. A chemical rest
c)
C. A hydrometer
d)
A or B
31.
Which of the following would not be cause for a refrigerating system to short cycle on HP cutout?
a)
Discharge valve leaking
b)
Pressure cutout set incorrectly
c)
System overcharged with refrigerant
d)
Insufficient cooling water
32.
Excessive head pressure is caused by:
a)
Air or noncondensable gas in the system
b)
Dirty condenser tubes
c)
Insufficient cooling water to condenser
d)
Any of these
33.
The capacity of a centrifugal type compressor is controlled by which of the following?
a)
A. Regulating the discharge pressure
b)
B. Regulating the speed
c)
C. Regulating the suction pressure
d)
B or C
34.
Where is solenoid coil installed?
a)
Vertically above the valve
b)
Horizontally above the valve
c)
Vertically below the valve
d)
Horizontally below the valve
35.
What is the condition of the compressor when purging a refrigeration system?
a)
The compressor is running
b)
Compressor is running but the condenser secured
c)
Shut down
d)
Running with the bypass open
36.
What must be done first opening a single packed stop valve?
a)
Loosen the packing before opening
b)
Tighten packing before opening
c)
Check to see that the seal is not scored
d)
None of these
37.
Excessive head pressure is caused by:
a)
A. Flooded condenser tubes
b)
B. Too much cooling water to condenser
c)
C. Cooling water temperature too high
d)
A or C
38.
Everything is in its normal operating position when charging a system except the _____.
a)
Compressor discharge valve
b)
Purge valve
c)
Solenoid valve
d)
King (receiver discharge) valve
39.
How often the condenser must be cleaned?
a)
Once a year
b)
Every month
c)
When pressure goes above normal
d)
Every 6 months
40.
Which do you think is the cause of a hot suction line of a refrigerating compressor?
a)
A. Lack of refrigerant
b)
B. Insufficient condensing cooling water
c)
C. Excess refrigeration
d)
B or C
41.
Which of the following vital components of the refrigeration system where both temperature and pressure are increased?
a)
A. Compressor
b)
B. Condenser
c)
C. Evaporator
d)
A or C
42.
The refrigerant temperature is at its maximum just before it enters the _____.
a)
Expansion valve
b)
Compressor
c)
Condenser
d)
evaporator
43.
The greatest decrease in refrigerant temperature occurs in the _____.
a)
A. Evaporator
b)
B. Compressor
c)
C. Condenser
d)
A or C
44.
What do you call the storage tank for liquid refrigerant?
a)
Receiver tank
b)
Charging tank
c)
Purging
d)
Any of these
45.
A precooler is sometimes installed between the _____.
a)
Compressor and condenser
b)
Condenser and expansion valve
c)
Expansion valve and evaporator
d)
Evaporator and compressor
46.
The solenoid valve controls which of the following?
a)
Pressure in the evaporator coils
b)
Amount of refrigerant entering the evaporator
c)
Flow of refrigerant to the expansion valve
d)
Amount of circulating water to the condenser
47.
Closing the solenoid valve will stop the compressor through the _____.
a)
Low water-pressure cutout switch
b)
Bypass relief valve
c)
Low-pressure cutout switch
d)
High-pressure cutout switch
48.
What are the four basic methods of determining whether the proper amount of refrigerant is being added to the system?
a)
bull’s-eye, weight, pressure and frost line
b)
Temperature, weight, pressure and frost line
c)
Bull’s-eye, weight, pressure and dip stick
d)
Bull’s-eye, weight, litmus test and frost line
49.
What is the cause of liquid “slugging”?
a)
Liquid in the compressor clearance space
b)
Excessive liquid refrigerant in the receiver
c)
The presence of liquid in the condenser causing excessive noise
d)
The pounding of liquid refrigerant in the suction line at a point of restriction
50.
Which of the following is also known as the “hidden heat” in refrigeration work?
a)
A. Sensible heat
b)
B. Heat intensity
c)
C. Latent heat
d)
A or C
51.
A bull’s eye in a full liquid line will appear _____.
a)
A. Cloudy
b)
B. Clear
c)
C. Latent
d)
A or C
52.
A compressor capacity reduction device reduces compressor capacity _____.
a)
By reducing the compressor speed
b)
By bypassing hot gas
c)
As the refrigerant load dictates
d)
By reducing compressor horsepower proportionately
53.
If a Freon-12 compressor trip out on “cut-out” the solenoid valve closes by which of the following?
a)
An electrical release
b)
Temperature and spring control
c)
Pressure and bellows control
d)
Bellows control
54.
The thickness of the head gasket is important because it may cause _____.
a)
Re-expansion
b)
Decreased efficiency due to increased clearance
c)
The piston to strike the head
d)
All of these
55.
If the expansion valve capillary tube is pinched, which of the following must be replaced?
a)
Tube
b)
Diaphragm
c)
Bulb
d)
All of the above (called the power element unit)
56.
When removing reusable refrigerant from a system, the line to the storage drum must
a)
Be made of copper
b)
Have no bends in it
c)
Contain a strainer-dryer
d)
Be above the level of the compressor
57.
Which of the following must be considered when adding or removing oil from a refrigerator unit?
a)
Use new oil
b)
Do not overcharge
c)
Watch crankcase pressure
d)
All of these
58.
Where is the excess refrigerant removed?
a)
Suction side of the system
b)
Discharge side of the system
c)
Bypass
d)
Charging side of the system
59.
A absolute trunk piston is used to _____.
a)
Absorb side thrust
b)
Seal off gas from crankcase
c)
Prevent oil from mixing with gas
d)
All of these
60.
How do you all the process of charging a solid to a liquid?
a)
Evaporation
b)
Vaporization
c)
Fusion
d)
Condensation
61.
If there is too much lube oil in the system, what must be done?
a)
Remove same at once
b)
Wait until next overhaul to remove
c)
Wait until next recharging to remove
d)
Any of these
62.
The temperature bulb of the thermo-expansion valve is attached to which of the following?
a)
Icebox coil
b)
Evaporator coil outlet
c)
Evaporator coil inlet
d)
Wall of the icebox
63.
What is the use of the suction pressure regulating valve?
a)
Cuts in the compressor
b)
Maintains the back pressure in the evaporator coils
c)
Cuts out the compressor
d)
Controls the expansion valve
64.
How is a one-ton plant described?
a)
Remove one ton of heat from the reefer box
b)
Melt one ton of ice in 24 hours
c)
Make one ton of ice in 24 hours
d)
Remove the heat required to melt one ton of ice in 24 hours
65.
The temperature bulb of the solenoid valve is attached to the _____.
a)
Icebox coil
b)
Wall of the icebox
c)
Evaporator coil inlet
d)
Evaporator coil outlet
66.
What usually happens if the specific gravity of the brine is too low?
a)
The brine will freeze
b)
Solids will deposits
c)
It will be more heat-absorbing
d)
All of these
67.
The cooling water regulator is automatically actuated by which of the following?
a)
The discharge pressure of the refrigerant
b)
The temperature of the refrigerant
c)
An electric relay
d)
A thermo relay
68.
What will happen to the capacity if the superheat is increased on the suction side?
a)
Increases
b)
Decreases
c)
Remains the same
d)
Will double
69.
Which do you think is very important in adjusting compressor “V” belts?
a)
Allow about ½” slack
b)
Make it as tight as possible
c)
Make belt just tight to turn pulley
d)
Keep belts parallel
70.
Which of the following is important for evaporator coils?
a)
It must turn placed in the top of the compartment
b)
It must be secured to the sides
c)
It should have air completely surrounding them
d)
It must placed in front of circulating fans
71.
If there were a 15°F to 20°F temperature differential between the temperature corresponding to the pressure at the compressor discharge and the temperature at the condenser outlet, it would probably indicate the need for_____
a)
More refrigerant
b)
Purging the system
c)
More circulating water
d)
Less circulating
72.
Horsepower per ton of refrigeration is expressed as:
a)
4.75/COP
b)
4.75 × COP
c)
COP/4.75
d)
4.75/COP
73.
What is the effect on saturated temperature if the pressure of the fluid is decreased?
a)
there is no effect
b)
saturation temperature decreases
c)
saturation temperature remains constant
d)
saturation temperature increases
74.
Which of the following is a type of evaporator?
a)
shell-and-tube- condenser
b)
sell-and-tube-water cooler
c)
oil lantern rings
d)
polyphase motors
75.
A refrigeration control that guards the compressor form overloads brought about by abruptly increases loads resulting from defrosting, warm products and others, is called:
a)
safety valve
b)
suction hold-back valve
c)
solenoid valve
d)
expansion valve
76.
What is the usual COP of a domestic refrigerator?
a)
Less than 1
b)
More than 1
c)
Equal to 1
d)
Depends upon the make of it
77.
Compare the refrigerating effect per unit mass of refrigerant circulated for a superheated cycle that produces useful cooling and a saturated cycle. for the same vaporizing and condensing temperature.
a)
lower for a superheated cycle
b)
greater for a saturated cycle
c)
the same
d)
greater for a superheated cycle
78.
What is the least number of compressor a multistage system that will use?
a)
three
b)
two
c)
four
d)
one
79.
What is the heat that is removed from the space to be cooled, which is the same as the heat absorbed by the cooling coils?
a)
heating capacity
b)
enthalpy
c)
work compression
d)
refrigerating effect
80.
Which of the following is not a possible location of service valve?
a)
Suction of compressor
b)
Discharge of compressor
c)
Outlet of liquid receiver
d)
Outlet of condenser
81.
A type of valve connected from discharge of compressor directly to suction that is normally closed and will open automatically only if there is high discharge pressure.
a)
Check valve
b)
Solenoid valve
c)
King valve
d)
Relief valve
82.
Use to increase the capacity of condenser.
a)
Water regulating valve
b)
Desuperheating coils
c)
Liquid-suction heat exchanger
d)
Condenser heating coils
83.
Is use to subcooled the refrigerant from the condenser.
a)
Liquid subcooler
b)
Condenser subcooler
c)
Desuperheating coils
d)
Liquid receiver
84.
Which of the following is NOT a part of low-pressure side in refrigeration system?
a)
Compressor
b)
Condenser
c)
Liquid line
d)
Suction line
85.
Which of the following is NOT a part of high-pressure side in refrigeration system?
a)
Compressor
b)
Condenser
c)
Liquid line
d)
Suction line
86.
Which of the following is NOT a part of condensing unit?
a)
Compressor
b)
Discharge line
c)
Condenser
d)
Liquid line
87.
By subcooling the refrigerant in refrigeration system, the compressor power per unit mass will _____.
a)
increase
b)
decrease
c)
remains the same
d)
none of these
88.
Superheating the refrigerant in refrigeration system without useful cooling, the refrigeration effect per unit mass will _____.
a)
increase
b)
decrease
c)
remains the same
d)
none of these
89.
By subcooling the refrigerant in refrigeration system, the specific volume at compressor suction will _____.
a)
increase
b)
decrease
c)
remains the same
d)
none of these
90.
Pressure loss due to friction at the condenser, the compressor power per unit mass will _____.
a)
increase
b)
decrease
c)
remains the same
d)
none of these
91.
A type of refrigerant control typically used in household refrigeration.
a)
Thermostatic expansion valve
b)
Automatic expansion valve
c)
Capillary tube
d)
High side float
92.
Type of condenser that operates like a cooling water.
a)
Air-cooled condenser
b)
Evaporative condenser
c)
Shell and tube condenser
d)
Water cooled condenser
93.
The major problem of heat pump is
a)
Refrigerant used
b)
Outside air
c)
Supply air
d)
Frosting
94.
Dominant refrigerant used in commercial refrigeration system.
a)
R11
b)
R22
c)
R12
d)
R502
95.
Cascade refrigerant system are connected in _____.
a)
Series
b)
Parallel
c)
Series-parallel
d)
Parallel
96.
Is use to heat up the solution partially before entering the generator in absorption refrigeration system.
a)
Rectifier
b)
Absorber
c)
Regenerator
d)
Pump
97.
The COP of actual absorption refrigeration system is usually _____.
a)
Less than 1
b)
Less than 2
c)
Less than 3
d)
Less than 4
98.
The ability of oil to mix with refrigerants.
a)
Carbonization
b)
Purging
c)
Mixing
d)
Miscibility
99.
By increasing the temperature source of Carnot cycle, which of the following will not be affected?
a)
Efficiency
b)
Work
c)
Heat added
d)
Heat rejected
100.
By decreasing the temperature sink of Carnot cycle, which of the following will not be affected?
a)
Efficiency
b)
Work
c)
Heat added
d)
Heat rejected
101.
By superheating the refrigerant in vapor compression cycle with useful cooling, which of the following will increase? (use per unit mass analysis)
a)
Condenser pressure
b)
Evaporator pressure
c)
Quality after expansion
d)
Heat rejected from condenser
102.
By superheating the refrigerant in vapor compression cycle with useful cooling, which of the following will decrease? (use per unit mass analysis)
a)
Refrigerating effect
b)
COP
c)
Compressor power
d)
Mass flow rate
103.
By superheating the refrigerant in vapor compression cycle without useful cooling, which of the following will decrease? (use per unit mass analysis)
a)
Heat rejected
b)
COP
c)
Compressor power
d)
Specific volume at suction
104.
By superheating the refrigerant in vapor compression cycle without useful cooling, which of the following will increase? (use per unit mass analysis)
a)
Heat rejected
b)
COP
c)
Compressor power
d)
Specific volume at suction
105.
By superheating the refrigerant in vapor compression cycle without useful cooling, which of the following will not be affected? (use per unit mass analysis)
a)
Refrigerating effect
b)
COP
c)
Compressor power
d)
Mass flow rate
106.
By sub-cooling the refrigerant in vapor compression cycle at condenser exit, which of the following will increase? (use per unit mass analysis)
a)
Refrigerating effect
b)
Specific volume at suction
c)
Compressor power
d)
Mass flow rate
107.
By sub-cooling the refrigerant in vapor compression cycle at condenser exit, which of the following will decrease? (use per unit mass analysis)
a)
Refrigerating effect
b)
Specific volume at suction
c)
Compressor power
d)
Mass flow rate
108.
By increasing the vaporizing temperature in vapor compression cycle, which of the following will increase? (Use per unit mass analysis)
a)
mass flow rate
b)
COP
c)
specific volume at suction
d)
compressor work
109.
By increasing the vaporizing temperature in vapor compression cycle, which of the following will decrease? (Use per unit mass analysis)
a)
Refrigeration effect
b)
COP
c)
evaporator temperature
d)
Temperature difference between evaporator and compressor
110.
By increasing the condenser pressure in vapor compression cycle, which of the following will increase? (Use per unit mass analysis)
a)
moisture content after expansion
b)
compressor power
c)
heat rejected from condenser
d)
mass flow rate
111.
If the pressure drop in the condenser Increases in a vapor compression cycle, which of the following will increase? (Use per unit mass analysis)
a)
mass flow rate
b)
compressor power
c)
heat rejected in the condenser
d)
specific volume of suction
112.
If the pressure drop in the condenser increases in a vapor compression cycle, which of the following will decrease? (Use per unit mass analysis)
a)
Refrigeration effect
b)
mass flow rate
c)
heat rejected in the condenser
d)
compressor power
113.
If the pressure drop in the condenser increases in a vapor compression cycle, which of the following will not be affected? (Use per unit mass analysis)
a)
compressor power
b)
mass flow rate
c)
heat rejection in the condenser
d)
COP
114.
If the pressure drop in the evaporator increases in a vapor compression cycle, which of the following will increase? (Use per unit mass analysis)
a)
Refrigerating effect
b)
vaporizing temperature
c)
heat rejected in the condenser
d)
COP
115.
If the pressure drop in the evaporator increases in a vapor compression cycle, which of the following will decrease? (Use per unit mass analysis)
a)
specific volume at suction
b)
compressor power
c)
heat rejected in the condenser
d)
COP
100 %
