Solution and Answer Guide
Review Test Answers
1. The standard atmospheric conditions for water to boil at 212°F are:
a. 15.969 psi at a temperature of 70°F.
b. 16.696 psi at a temperature of 68°F.
c. 14.696 psi at a temperature of 70°F.
d. 15.696 psi at a temperature of 68°F.
Answer: c
2. At standard conditions, water will boil at _____ on the Celsius scale.
a. 100°C
b. 212°C
c. 32°C
d. 0°C
Answer: a
Solution and Answer Guide: Silberstein/Obrzut, The Complete HVACR Manual 2E, 9780357618738; Section 1: HVACR Core Concepts (HCC)
3. If water weighs 8.33 pounds per gallon, it will take _____ Btu to raise the temperature of 4 gallons of water from 70°F to 72°F.
a. 66.7
b. 10
c. 14.7
d. 106
Answer: a
4. Heat energy flows from a warmer substance to a cooler substance.
a. True
b. False
Answer: a
5. When heat transfers by conduction, it:
a. moves through space and air and heats only solid objects.
b. is transported from one place to another by air or liquid.
c. moves from molecule to molecule within the substance.
d. All of the above.
Answer: c
6. When heat transfers by convection, it:
a. moves through space and air and heats only solid objects.
b. is transported from one place to another by air or liquid.
c. moves from molecule to molecule within the substance.
d. All of the above.
Answer: b
7. When heat transfers by radiation, it:
a. moves through space and air and heats only solid objects.
b. is transported from one place to another by air or liquid.
c. moves from molecule to molecule within the substance.
d. All of the above.
Answer: a
8. Sensible heat energy levels:
a. can be measured with a thermometer.
b. are known as hidden heat levels.
c. are always in the comfort range.
d. result in a change of state of the substance.
Answer: a
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Solution and Answer Guide: Silberstein/Obrzut, The Complete HVACR Manual 2E, 9780357618738; Section 1: HVACR Core Concepts (HCC)
9. Latent heat energy levels:
a. can be measured with a thermometer.
b. are determined with a barometer.
c. are always very warm.
d. result in a change of state of the substance.
Answer: d
10. The atmosphere will support a column of mercury ______ in high at sea level.
a. 32.00
b. 28.69
c. 14.696
d. 29.92
Answer: d
11. A Bourdon tube can be found in a:
a. mercury barometer.
b. aneroid barometer.
c. pressure gauge.
d. mercury thermometer.
Answer: c
12. Psig is equal to:
a. psia + 14.696.
b. psia - 14.696.
c. psia + 16.696.
d. psia - 16.696.
Answer: b
13. 98°C is equal to:
a. 214.6°F.
b. 196.0°F.
c. 119.8°F.
d. 208.4°F.
Answer: d
14. 70°F is equal to:
a. 21.1°C.
b. 22.6°C.
c. 98.6°C.
d. 20.3°C.
Answer: a
Solution and Answer Guide: Silberstein/Obrzut, The Complete HVACR Manual 2E, 9780357618738; Section 1: HVACR Core Concepts (HCC)
15. The density of a substance:
a. is used to measure its energy.
b. describes its mass-to-volume relationship.
c. is used to determine the transferability of heat.
d. determines its ability to attract unlike magnetic charges.
Answer: b
16. How many ft-lb of work is done when a 500 lb condensing unit is lifted to the top of a 60 ft building?
a. 560 ft-lb
b. 440 ft-lb
c. 8.33 ft-lb
d. 30,000 ft-lb
Answer: d
17. Moving 66-lb object a distance of 1,000 feet in one minute is the equivalent of
a. 0.5 hp
b. 1.0 hp
c. 1.5 hp
d. 2.0 hp
Answer: d
18. A compound gauge can be used to measure pressures:
a. above and below atmospheric pressure.
b. that are only expressed in psia.
c. that are only below 0 psig.
d. that are only above 0 psig.
Answer: a
19. When a substance is heated, the molecules:
a. move slower.
b. move faster.
c. move at the same speed.
d. stop moving.
Answer: b
20. The latent heat of fusion for a water-to-ice transformation is:
a. 1 Btu/lb.
b. 144 Btu/lb.
c. 288 Btu/lb.
d. 970 Btu/lb.
Answer: b
Solution and Answer Guide: Silberstein/Obrzut, The Complete HVACR Manual 2E, 9780357618738; Section 1: HVACR Core Concepts (HCC)
21. If the specific gravity of copper is 8.91, its density is:
a. 55.6 lb/ft3 .
b. 238.8 lb/ft3 .
c. 23.88 lb/ft3 .
d. 556 lb/ft3
Answer: d
22. Specific volume is used to:
a. compare the densities of various liquids.
b. compare the densities of various solids.
c. indicate the volume that a specific weight of gas will occupy.
d. describe the energy characteristics of a substance.
Answer: c
23. Gas molecules push outward in:
a. a downward direction.
b. an upward direction.
c. a sideways direction.
d. All of the above.
Answer: d
24. An example of a fossil fuel is:
a. natural gas.
b. hydrogen.
c. wood.
d. liquid oxygen.
Answer: a
25. Work is equal to:
a. force × power.
b. force × energy.
c. force × distance.
d. distance × energy.
Answer: c
Solution and Answer Guide: Silberstein/Obrzut, The Complete HVACR Manual 2E, 9780357618738; Section 1: HVACR Core Concepts (HCC)
Exercise HCC-1 Completed Temperature Conversion Chart
(Bolded values in parentheses represent the items that were to be filled in by the student.)
Exercise HCC-1 Answers to Questions
1. The mathematical relationship between a Fahrenheit temperature and the equivalent Celsius temperature is:
a. 1:1.
b. 2:1.
c. 3:1.
d. It cannot be determined, as the values are not proportional.
Answer: d
2. Which of the following temperature scales represent absolute values?
a. Celsius and Kelvin
b. Fahrenheit and Celsius
c. Kelvin and Rankine
d. Fahrenheit and Kelvin
Answer: c
Solution and Answer Guide: Silberstein/Obrzut, The Complete HVACR Manual 2E, 9780357618738; Section 1: HVACR Core Concepts (HCC)
3. Which of the following temperatures represents absolute zero?
a. 460°F
b. 0°C
c. 672°R
d. 273°K
Answer: a
4. Which of the following temperatures is the coldest?
a. 32°F
b. 672°R
c. 100°C
d. 373°K
Answer: a
5. Which of the following temperatures is the hottest?
a. 212°F
b. 492°R
c. 273°K
d. 0°C
Answer: a
6. Which of the following temperatures represent the same level of heat intensity?
a. 0°C and 0°K
b. 0°F and 0°R
c. 40°C and 40°F
d. 50°C and 50°R
Answer: c
Exercise HCC-2 Answers to Questions
1. How does the rate of temperature rise of the 8 oz water sample compare to the rate of temperature rise of the 16 oz water sample?
a. The rate of temperature rise of the 8 oz water sample was greater than the rate of temperature rise of the 16 oz water sample.
b. The rate of temperature rise of the 16 oz water sample was greater than the rate of temperature rise of the 8 oz water sample.
c. The rate of temperature rise of the 8 oz water sample was the same as the rate of temperature rise of the 16 oz water sample.
Answer: a
Solution and Answer Guide: Silberstein/Obrzut, The Complete HVACR Manual 2E, 9780357618738; Section 1: HVACR Core Concepts (HCC)
2. How does the amount of heat energy absorbed by the water or saltwater solution relate to the amount of heat energy produced by the burner?
a. The amount of heat produced by the burner is greater.
b. The amount of heat absorbed by the water is greater.
c. The amount of heat absorbed by the saltwater is greater.
d. The amount of heat produced by the burner is equal to the amount of heat absorbed by the water.
Answer: a
3. With regards to this laboratory exercise, which of the following is an example of heat loss?
a. The support ring getting hot.
b. The glass beaker getting hot.
c. The air around the beaker getting hot.
d. All of the above are examples of heat losses.
Answer: d
4. Based on the results of this laboratory exercise, it can be concluded that:
a. impurities added to water will increase the rate of temperature rise of the solution.
b. impurities added to water will decrease the rate of temperature rise of the solution.
c. impurities added to water will neither increase nor decrease the rate of temperature rise of the solution.
Answer: b
Exercise HCC-3 Answers to Questions
1. How does the rate of temperature rise of the glass rod compare to the rate of temperature rise of the copper tubing?
a. The rate of temperature rise of the glass rod was greater than the rate of temperature rise of the copper tubing.
b. The rate of temperature rise of the copper tubing was greater than the rate of temperature rise of the glass rod.
c. The rate of temperature rise of the glass rod was the same as the rate of temperature rise of the copper tubing.
Answer: b
2. Based on this exercise and your knowledge of electron theory, what can likely be concluded about the glass rod and the copper tubing?
a. Glass is a good conductor, while copper is a good insulator.
b. Glass is a good insulator, while copper is a good conductor.
c. Glass and copper are both good insulators.
d. Glass and copper are both good conductors.
Answer: b
Solution and Answer Guide: Silberstein/Obrzut, The Complete HVACR Manual 2E, 9780357618738; Section 1: HVACR Core Concepts (HCC)
3. Explain the relationship, if any, that exists between a substance being either a good conductor of heat and electricity or a good insulator.
Answer: Substances that are good conductors of electricity also tend to be good conductors of heat.
Exercise HCC-4 Completed Chart
(Bolded values in parentheses represent the items that were to be filled in by the student.) Substance
(0.7) (11.2) 1208 (19.36) (GOLD) (SINK) B (0.036) (0.58) (62.4) 1 (WATER) N/A
(0.317) (5.07) (548) (8.78) RED BRASS (SINK)
0.3218 (5.15) (556) (8.91) (COPPER) (SINK)
(0.033) 0.5324 (57.5) (0.92) (ICE) (FLOAT) F (0.099) (1.58) 171 (2.74) (ALUMINUM) (SINK) G (0.70) (11.2) (1210) 19.39 (TUNGSTEN) (SINK)
H (0.094) (1.5) (162) (2.596) MARBLE (SINK)
Exercise HCC-4 Answers to Questions
1. From the completed chart, which of the substances will float if placed in a container of water?
a. Substances A, D, and E
b. Substances A and B
c. Substances B and H
d. Only Substance E
Answer: d
2. From the completed chart, which of the substances is about three times as dense as water?
a. Red brass
b. Gold
c. Aluminum
d. Copper
Answer: c
Solution and Answer Guide: Silberstein/Obrzut, The Complete HVACR Manual 2E, 9780357618738; Section 1: HVACR Core Concepts (HCC)
3. Which of the following mathematical expressions best describes the conversion between lb/in.3 and lb/ft3?
a. (12 in./ft) (12 in./ft) (12 in./ft)
b. (12 in./ft) + (12 in./ft)
c. (12 in./ft) (12 in./ft)
d. (12 in./ft) + (12 in./ft) + (12 in./ft)
Answer: a
4. From the completed chart, which two substances have the most similar densities?
a. Gold and tungsten
b. Aluminum and marble
c. Red brass and copper
d. Water and ice
Answer: a
Exercise HCC-5 Completed Chart
(Bolded values in parentheses represent the items that were to be filled in by the student.)
Exercise HCC-5 Answers to Questions
1. Which two properties of gases are directly proportional to each other?
a. Pressure and temperature
b. Pressure and volume
c. Volume and temperature
d. Both A and C are correct
Answer: d
2. Which two properties of gases are inversely proportional to each other?
a. Pressure and temperature
b. Pressure and volume
c. Volume and temperature
d. Both B and C are correct
Answer: b
Solution and Answer Guide: Silberstein/Obrzut, The Complete HVACR Manual 2E, 9780357618738; Section 1: HVACR Core Concepts (HCC)
3. State Boyle’s Gas Law, Charles’ Gas Law, and the General Law of Perfect Gases.
Answer: Boyle’s law = P1 × V1 = P2 × V2, Charles’ law = V1÷T1 = V2 ÷ T2, General law = (P1 × V1) ÷ T1 = (P2 × V2) ÷ T2.
4. Explain why it is important to use absolute temperatures and pressures when using the various gas formulas.
Answer: Absolute pressure and temperature scales both have zero as their lowest values, so any pressure above 0 psia or temperature above zero degrees Rankin will be indicated by positive values. By keeping all of the values positive, the gas law will be a linear relationship existing among the pressure, temperature, and volume of the gas. If non-absolute scales are used, the relationships become non-linear and significant calculation errors can, and will, arise.
Exercise HCC-6 Completed Chart
(Bolded values in parentheses represent the items that were to be filled in by the student.)
Exercise HCC-6 Answers to Questions
1. Which formula correctly relates heat energy to watts?
a. 3.413 Btu = 1 W
b. 3.413 Btu/h = 1 W
c. 3.413 W = 1 Btu
d. 3.413 W = 1 Btu/h
Answer: b
Solution and Answer Guide: Silberstein/Obrzut, The Complete HVACR Manual 2E, 9780357618738; Section 1: HVACR Core Concepts (HCC)
2. If the time it takes to move an object a certain distance increases, then:
a. the amount of work done increases.
b. the amount of work done decreases.
c. the horsepower decreases.
d. the horsepower increases.
Answer: d
3. Which of the following represents the greatest horsepower?
a. Moving a 10 lb object 3300 ft in 2 minutes
b. Moving a 10 lb object 33,000 ft in 2 minutes
c. Moving a 10 lb object 3300 ft in 1 minute
d. Moving a 1 lb object 3300 ft in 10 minutes
Answer: b
4. What would the Btu/h output of a 25 kW electric heater be?
a. 0.853 Btu/h
b. 85,325 Btu/h
c. 85.32 Btu/h
d. 8.53 Btu/h
Answer: b
Exercise HCC-7 Answers to Questions
1. Explain why the backseated position is the only service valve position that will result in no refrigerant loss when removing a refrigerant hose from the service port.
Answer: In the backseated position, the gauge port is completely closed. This will seal the system and prevent the loss of refrigerant.
2. Explain why it is strongly recommended that the service port caps be placed on the mani-folds blank ports when refrigerant hoses are connected to the system’s service valves.
Answer: The service port caps are small and easy to misplace. Putting them on the blank ports helps keep track of them and serves as a reminder to the technician to put them back on when the hoses are removed from the system.
3. Explain what can happen if both manifold valves are in the open position and both (liquid line and suction line) service valves are cracked off the backseat on an operating airconditioning or refrigeration system.
Answer: Refrigerant liquid from the high-pressure side can travel through the manifold to the low-pressure side and enter the vapor line. This can result in liquid slugging and compressor damage or failure.
4. Explain the importance of replacing the stem caps on the service valves.
Answer: The stems of a service valve are susceptible to leaks. Keeping the caps in place can help prevent refrigerant loss in the event of a leak.
Solution and Answer Guide: Silberstein/Obrzut, The Complete HVACR Manual 2E, 9780357618738; Section 1: HVACR Core Concepts (HCC)
5. Explain why it is important to use only a refrigeration service wrench on the stems of service valves.
Answer: If pliers or other tools are used, the stem can become stripped and become very difficult to open or close.
6. Explain why gauge calibration should only be done when the hoses are disconnected from the blank ports on the gauge manifold.
Answer: Refrigerant oil may coat the inside of the gauge manifold and hoses. Refrigerant trapped in that oil may boil, adding pressure to the hoses and manifold. Taking the hoses off ensures that the gauges are at atmospheric pressure (0 psig).
Smith/Simmons, Electricity for Refrigeration, Heating and Air Conditioning, ©2003, 9780357618707, Chapter 1: Electrical Safety
Solution and Answer Guide
Smith/Simmons, Electricity for Refrigeration, Heating and Air Conditioning, ©2023, 9780357618707, Chapter 1: Electrical Safety
Table of Contents
End of Chapter Review Questions 1
End of Chapter Review Questions
1. True or False: A heating and air-conditioning service technician can usually troubleshoot heating and air-conditioning systems without the voltage being supplied to the equipment.
Answer: False
2. What is a live electrical circuit?
Solution a circuit that is being supplied with electrical potential (voltage)
3. Which of the following voltages will a refrigeration, heating, and air-conditioning technician come in contact with in the industry?
a. 24 volts
b. 120 volts
c. 240 volts
d. All of the choices are correct
Answer: d
4. Electrical shock occurs when a person _________.
a. touches an insulated wire
b. touches an electric motor
c. becomes part of an electric circuit
d. touches a conductor that has power applied to it, but is making contact with a ground
Answer: c
Smith/Simmons, Electricity for Refrigeration, Heating and Air Conditioning, ©2003, 9780357618707, Chapter 1: Electrical Safety
5. What are the important elements of electrical safety when working around live circuits?
Solution
• Respect electricity.
• Do not be careless.
• Make sure electrical power is disconnected from circuits that are being worked on if possible.
• Learn the safety rules in section 1.7 of this chapter.
6. Which of the following conditions is the most dangerous and likely to cause serious injury?
a. The technician touches a ground with his thumb and a live wire with his index finger.
b. The technician touches a live wire with his hand but is standing on an insulated platform.
c. The technician touches a live wire with his right hand and accidentally touches his right elbow on the metal part of the same unit.
d. The technician touches a live conductor with his right hand and touches a ground with his left hand.
Answer: d
7. Which of the following is the standard by which electrical installations are measured in the United States?
a. National Electrical Code®
b. United Electrical Code®
c. Basic Electrical Code®
d. none of the choices are correct
Answer: a
8. True or False: A current flow of 0.1 ampere or less could be fatal.
Answer: True
9. What type of ladder would be the best choice for the technician to use on the job?
a. aluminum
b. wood
c. fiberglass
d. steel
Answer: c
10. What precautions should be taken when you see a coworker receiving an electrical shock?
Solution
Never touch a person who is receiving an electrical shock.
Smith/Simmons, Electricity for Refrigeration, Heating and Air Conditioning, ©2003, 9780357618707, Chapter 1: Electrical Safety
11. True or False: It is recommended that at least one person on a truck know CPR.
Answer: True
12. True or False: The correct fuse size for an electrical circuit is one that is sized twice as large as needed for circuit protection.
Answer: False
13. What is the difference between a two-prong plug and a three-prong plug?
Solution
A three-prong plug has a ground, while a two-prong plug does not.
14. Which prong on a three-prong plug is the ground?
a. the left flat prong
b. the right flat prong
c. the center semicircular prong
d. none of the choices are correct
Answer: c
15. True or False: A grounding adapter does no good if it is not connected to an electrical ground.
Answer: True
16. An electrical device that will open an electrical circuit, preventing current flow to the circuit if a small leak to ground is detected, is called a _________.
a. GFCI
b. common circuit breaker
c. fuse
d. receptacle
Answer: a
17. True or False: Receptacles used on the job site should be protected with a GFCI.
Answer: True
18. What precautions should you use when working in an area with a large number of people and you must disconnect the power from an appliance you are working on?
Solution
Lock out circuit being serviced.
Smith/Simmons, Electricity for Refrigeration, Heating and Air Conditioning, ©2003, 9780357618707, Chapter 1: Electrical Safety
19. What is the difference between a fuse and a circuit breaker?
Solution
A fuse will have to be replaced when an overload occurs, while a circuit breaker will only have to be reset.
20. List at least five electrical safety rules that should be followed by refrigeration, heating, and air-conditioning technicians.
Solution
Answer should contain five rules from section 1.7 (Electrical Safety Guidelines)
21. Which of the following Injuries could be caused by an electrical shock?
a. burns
b. ventricular fibrillation of the heart
c. Injury to body parts caused by reaction of an electrical shock
d. all the choices are correct
Answer: d
22. What is the danger when the path of an electron flow is passed near or through the heart?
Solution
When the path of electrical flow crosses the heart, the risk of serious injury increases. Most fatal electrical accidents happen when the electrical flow passes near or through the heart. When the electrical path crosses near or through the heart for only a short period of time, it can cause ventricular fibrillation of the heart, in which the heart only flutters instead of beats and the blood flow to the body stops. Unless the heartbeat is returned to normal quickly with immediate medical attention, the person will usually die.