Nevada NV C-21B Air
Conditioning Contractor Practice
Exam Questions & Verified
Answers | Complete License
Exam Prep Study Guide |
Updated 2026
1. What is the primary purpose of an air-conditioning
system?
A. To increase indoor temperature
B. To control indoor temperature and, when designed to do so,
humidity
C. To provide electrical power
D. To replace all ventilation requirements
Correct Answer: To control indoor temperature and,
when designed to do so, humidity
Rationale: Air-conditioning equipment removes heat
from indoor spaces and can also control humidity.
Ventilation and air conditioning are related but are not
identical functions.
2. What type of heat causes a change in temperature
without a change of state?
A. Latent heat
B. Sensible heat
C. Compression heat
D. Radiant heat
Correct Answer: Sensible heat
Rationale: Sensible heat changes the temperature of a
substance without changing its physical state.
,3. What type of heat is associated with a change of
state?
A. Sensible heat
B. Latent heat
C. Static heat
D. Specific heat
Correct Answer: Latent heat
Rationale: Latent heat is absorbed or released during a
phase change such as evaporation or condensation
without necessarily changing the temperature.
4. What is the primary function of the evaporator coil in
a cooling system?
A. Reject heat outdoors
B. Absorb heat from indoor air
C. Compress refrigerant
D. Meter electrical current
Correct Answer: Absorb heat from indoor air
Rationale: The evaporator is the low-pressure heat-
absorbing component. Indoor air transfers heat to the
refrigerant flowing through the evaporator.
5. What is the primary function of the condenser?
A. Absorb indoor heat
B. Meter refrigerant
C. Reject heat to the surroundings
D. Increase indoor humidity
Correct Answer: Reject heat to the surroundings
,Rationale: The condenser rejects heat absorbed from
the conditioned space plus the heat added by the
compressor.
6. What component separates the high-pressure side
from the low-pressure side by restricting refrigerant
flow?
A. Expansion device
B. Accumulator
C. Receiver
D. Filter-drier
Correct Answer: Expansion device
Rationale: The expansion device creates a pressure drop
between the high side and low side and meters
refrigerant into the evaporator.
7. What happens to refrigerant pressure as it passes
through a typical expansion device?
A. It increases substantially
B. It decreases
C. It remains exactly constant
D. It becomes atmospheric pressure
Correct Answer: It decreases
Rationale: The expansion device creates a pressure drop
that allows the refrigerant to evaporate at a lower
temperature in the evaporator.
8. Where is refrigerant normally in a superheated vapor
state in a basic vapor-compression system?
A. Leaving the compressor
B. Leaving the expansion valve
, C. Leaving the condenser as a liquid
D. Inside the receiver as liquid
Correct Answer: Leaving the compressor
Rationale: The compressor raises the pressure and
temperature of the refrigerant vapor, producing high-
pressure, high-temperature discharge gas.
9. What does superheat measure?
A. Liquid temperature below saturation
B. Vapor temperature above its saturation temperature
C. Condenser temperature below ambient
D. Compressor temperature below suction temperature
Correct Answer: Vapor temperature above its saturation
temperature
Rationale: Superheat is the difference between actual
vapor temperature and saturation temperature at the
measured pressure.
10. What does subcooling indicate?
A. Vapor temperature above saturation
B. Liquid temperature below its saturation temperature
C. Compressor temperature above discharge temperature
D. Suction pressure above head pressure
Correct Answer: Liquid temperature below its saturation
temperature
Rationale: Subcooling is the difference between the
refrigerant's saturation temperature and the actual
liquid temperature.
11. Why is superheat important at the compressor inlet?
Conditioning Contractor Practice
Exam Questions & Verified
Answers | Complete License
Exam Prep Study Guide |
Updated 2026
1. What is the primary purpose of an air-conditioning
system?
A. To increase indoor temperature
B. To control indoor temperature and, when designed to do so,
humidity
C. To provide electrical power
D. To replace all ventilation requirements
Correct Answer: To control indoor temperature and,
when designed to do so, humidity
Rationale: Air-conditioning equipment removes heat
from indoor spaces and can also control humidity.
Ventilation and air conditioning are related but are not
identical functions.
2. What type of heat causes a change in temperature
without a change of state?
A. Latent heat
B. Sensible heat
C. Compression heat
D. Radiant heat
Correct Answer: Sensible heat
Rationale: Sensible heat changes the temperature of a
substance without changing its physical state.
,3. What type of heat is associated with a change of
state?
A. Sensible heat
B. Latent heat
C. Static heat
D. Specific heat
Correct Answer: Latent heat
Rationale: Latent heat is absorbed or released during a
phase change such as evaporation or condensation
without necessarily changing the temperature.
4. What is the primary function of the evaporator coil in
a cooling system?
A. Reject heat outdoors
B. Absorb heat from indoor air
C. Compress refrigerant
D. Meter electrical current
Correct Answer: Absorb heat from indoor air
Rationale: The evaporator is the low-pressure heat-
absorbing component. Indoor air transfers heat to the
refrigerant flowing through the evaporator.
5. What is the primary function of the condenser?
A. Absorb indoor heat
B. Meter refrigerant
C. Reject heat to the surroundings
D. Increase indoor humidity
Correct Answer: Reject heat to the surroundings
,Rationale: The condenser rejects heat absorbed from
the conditioned space plus the heat added by the
compressor.
6. What component separates the high-pressure side
from the low-pressure side by restricting refrigerant
flow?
A. Expansion device
B. Accumulator
C. Receiver
D. Filter-drier
Correct Answer: Expansion device
Rationale: The expansion device creates a pressure drop
between the high side and low side and meters
refrigerant into the evaporator.
7. What happens to refrigerant pressure as it passes
through a typical expansion device?
A. It increases substantially
B. It decreases
C. It remains exactly constant
D. It becomes atmospheric pressure
Correct Answer: It decreases
Rationale: The expansion device creates a pressure drop
that allows the refrigerant to evaporate at a lower
temperature in the evaporator.
8. Where is refrigerant normally in a superheated vapor
state in a basic vapor-compression system?
A. Leaving the compressor
B. Leaving the expansion valve
, C. Leaving the condenser as a liquid
D. Inside the receiver as liquid
Correct Answer: Leaving the compressor
Rationale: The compressor raises the pressure and
temperature of the refrigerant vapor, producing high-
pressure, high-temperature discharge gas.
9. What does superheat measure?
A. Liquid temperature below saturation
B. Vapor temperature above its saturation temperature
C. Condenser temperature below ambient
D. Compressor temperature below suction temperature
Correct Answer: Vapor temperature above its saturation
temperature
Rationale: Superheat is the difference between actual
vapor temperature and saturation temperature at the
measured pressure.
10. What does subcooling indicate?
A. Vapor temperature above saturation
B. Liquid temperature below its saturation temperature
C. Compressor temperature above discharge temperature
D. Suction pressure above head pressure
Correct Answer: Liquid temperature below its saturation
temperature
Rationale: Subcooling is the difference between the
refrigerant's saturation temperature and the actual
liquid temperature.
11. Why is superheat important at the compressor inlet?
