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 outdoor humidity
B. To control indoor temperature and related comfort conditions
C. To provide electrical power to a building
D. To replace all building ventilation
Correct Answer: To control indoor temperature and related comfort
conditions
Rationale: Air-conditioning systems remove heat from indoor
spaces and may also control humidity, air movement, filtration, and
ventilation as part of the overall system.
2. What type of heat causes a change in temperature without a change of
state?
A. Latent heat
B. Sensible heat
C. Specific heat
D. Radiant heat
Correct Answer: Sensible heat
Rationale: Sensible heat changes the measurable 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. Conductive heat
Correct Answer: Latent heat
Rationale: Latent heat is absorbed or released during a phase
change such as evaporation or condensation without necessarily
changing temperature.
4. What happens to refrigerant in the evaporator?
A. It rejects heat to outdoor air
B. It absorbs heat from the conditioned space
C. It is compressed into a high-pressure vapor
D. It is subcooled by the condenser fan
Correct Answer: It absorbs heat from the conditioned space
Rationale: The evaporator is the heat-absorbing component.
Refrigerant evaporates at a low pressure and temperature while
absorbing heat from the air or other medium.
5. What is the primary function of the compressor?
A. Lower refrigerant pressure
B. Remove moisture from the air
C. Raise refrigerant vapor pressure and temperature
D. Meter liquid refrigerant into the evaporator
Correct Answer: Raise refrigerant vapor pressure and temperature
Rationale: The compressor takes in low-pressure vapor and
compresses it into a high-pressure, high-temperature vapor before it
enters the condenser.
6. What is the primary function of the condenser?
,A. Absorb heat from the conditioned space
B. Reject heat from the refrigerant
C. Meter refrigerant flow
D. Filter indoor air
Correct Answer: Reject heat from the refrigerant
Rationale: The condenser removes heat from the refrigerant and
transfers it to the outdoor environment, causing the refrigerant to
condense into a liquid.
7. What is the function of a thermostatic expansion valve?
A. Compress refrigerant
B. Meter refrigerant into the evaporator
C. Remove oil from the compressor
D. Increase condenser airflow
Correct Answer: Meter refrigerant into the evaporator
Rationale: A TXV regulates refrigerant flow into the evaporator
based primarily on evaporator load and outlet superheat.
8. What is superheat?
A. Temperature of liquid below its condensing point
B. Temperature of vapor above its saturation temperature
C. Pressure of liquid above atmospheric pressure
D. Temperature of outdoor air above design temperature
Correct Answer: Temperature of vapor above its saturation temperature
Rationale: Superheat is calculated by subtracting the refrigerant
saturation temperature from the actual vapor temperature at the
same pressure.
, 9. What is subcooling?
A. Cooling vapor below room temperature
B. Cooling liquid below its saturation temperature
C. Heating liquid above its saturation temperature
D. Cooling compressor oil below freezing
Correct Answer: Cooling liquid below its saturation temperature
Rationale: Subcooling indicates how far liquid refrigerant has been
cooled below its saturation temperature at the measured pressure.
10. Where is superheat normally measured in a conventional cooling
system?
A. Compressor discharge line only
B. Evaporator outlet or suction line
C. Condenser liquid line only
D. Electrical disconnect
Correct Answer: Evaporator outlet or suction line
Rationale: Evaporator outlet superheat indicates how much the
refrigerant vapor has been heated above saturation after leaving the
evaporator.
11. Which component separates low-pressure vapor from liquid refrigerant
and helps protect a compressor from liquid floodback?
A. Receiver
B. Accumulator
C. Filter-drier
D. Condenser
Correct Answer: Accumulator
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 outdoor humidity
B. To control indoor temperature and related comfort conditions
C. To provide electrical power to a building
D. To replace all building ventilation
Correct Answer: To control indoor temperature and related comfort
conditions
Rationale: Air-conditioning systems remove heat from indoor
spaces and may also control humidity, air movement, filtration, and
ventilation as part of the overall system.
2. What type of heat causes a change in temperature without a change of
state?
A. Latent heat
B. Sensible heat
C. Specific heat
D. Radiant heat
Correct Answer: Sensible heat
Rationale: Sensible heat changes the measurable 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. Conductive heat
Correct Answer: Latent heat
Rationale: Latent heat is absorbed or released during a phase
change such as evaporation or condensation without necessarily
changing temperature.
4. What happens to refrigerant in the evaporator?
A. It rejects heat to outdoor air
B. It absorbs heat from the conditioned space
C. It is compressed into a high-pressure vapor
D. It is subcooled by the condenser fan
Correct Answer: It absorbs heat from the conditioned space
Rationale: The evaporator is the heat-absorbing component.
Refrigerant evaporates at a low pressure and temperature while
absorbing heat from the air or other medium.
5. What is the primary function of the compressor?
A. Lower refrigerant pressure
B. Remove moisture from the air
C. Raise refrigerant vapor pressure and temperature
D. Meter liquid refrigerant into the evaporator
Correct Answer: Raise refrigerant vapor pressure and temperature
Rationale: The compressor takes in low-pressure vapor and
compresses it into a high-pressure, high-temperature vapor before it
enters the condenser.
6. What is the primary function of the condenser?
,A. Absorb heat from the conditioned space
B. Reject heat from the refrigerant
C. Meter refrigerant flow
D. Filter indoor air
Correct Answer: Reject heat from the refrigerant
Rationale: The condenser removes heat from the refrigerant and
transfers it to the outdoor environment, causing the refrigerant to
condense into a liquid.
7. What is the function of a thermostatic expansion valve?
A. Compress refrigerant
B. Meter refrigerant into the evaporator
C. Remove oil from the compressor
D. Increase condenser airflow
Correct Answer: Meter refrigerant into the evaporator
Rationale: A TXV regulates refrigerant flow into the evaporator
based primarily on evaporator load and outlet superheat.
8. What is superheat?
A. Temperature of liquid below its condensing point
B. Temperature of vapor above its saturation temperature
C. Pressure of liquid above atmospheric pressure
D. Temperature of outdoor air above design temperature
Correct Answer: Temperature of vapor above its saturation temperature
Rationale: Superheat is calculated by subtracting the refrigerant
saturation temperature from the actual vapor temperature at the
same pressure.
, 9. What is subcooling?
A. Cooling vapor below room temperature
B. Cooling liquid below its saturation temperature
C. Heating liquid above its saturation temperature
D. Cooling compressor oil below freezing
Correct Answer: Cooling liquid below its saturation temperature
Rationale: Subcooling indicates how far liquid refrigerant has been
cooled below its saturation temperature at the measured pressure.
10. Where is superheat normally measured in a conventional cooling
system?
A. Compressor discharge line only
B. Evaporator outlet or suction line
C. Condenser liquid line only
D. Electrical disconnect
Correct Answer: Evaporator outlet or suction line
Rationale: Evaporator outlet superheat indicates how much the
refrigerant vapor has been heated above saturation after leaving the
evaporator.
11. Which component separates low-pressure vapor from liquid refrigerant
and helps protect a compressor from liquid floodback?
A. Receiver
B. Accumulator
C. Filter-drier
D. Condenser
Correct Answer: Accumulator
