Nevada C-21 Refrigeration & Air Conditioning Maintenance Contractor Practice
Exam 200 Que, Exams of Engineering.
SECTION 1: Refrigeration Cycle & Basic Principles (Questions 1-25)
Question 1
What is the primary purpose of a refrigeration system in an air conditioning
setup?
A) Increase indoor humidity
B) Remove heat from a space
C) Circulate air only
D) Generate electricity
Answer: B
Rationale: The primary purpose of a refrigeration system is to remove heat from a
designated space to maintain desired temperatures. This is the fundamental
principle of mechanical refrigeration .
Question 2
In the vapor-compression cycle, which component absorbs heat from the
conditioned space?
,A) Compressor
B) Condenser
C) Expansion valve
D) Evaporator
Answer: D
Rationale: The evaporator allows low-pressure liquid refrigerant to boil and turn
into a gas, absorbing latent heat from the indoor air passing over its coils. This is
where the actual cooling occurs .
Question 3
What is the term for heat that changes the temperature of a substance without
changing its physical state?
A) Latent heat
B) Superheat
C) Subcooling
D) Sensible heat
,Answer: D
Rationale: Sensible heat is the energy added or removed that causes a change in
temperature that can be measured with a thermometer. Latent heat causes
phase changes without temperature change .
Question 4
What is "Latent Heat"?
A) Heat that can be felt on a thermometer
B) Heat required to change the state of a substance without changing
temperature
C) Heat generated by friction in the compressor
D) Heat lost through ductwork
Answer: B
Rationale: Latent heat is "hidden" heat. In HVAC, it is the energy required to
evaporate water or refrigerant, contributing to humidity control. Sensible heat
changes temperature .
Question 5
, The term "Superheat" refers to:
A) The temperature of the refrigerant in the condenser
B) The temperature of the vapor refrigerant above its saturation temperature
C) The temperature of the liquid refrigerant below its saturation point
D) The outdoor ambient temperature plus the heat of compression
Answer: B
Rationale: Superheat is the difference between the actual temperature of the
refrigerant vapor and its saturation temperature at the same pressure. It ensures
no liquid enters the compressor .
Question 6
In a refrigeration system, the term "subcooling" refers to:
A) Reducing the temperature of the suction gas below ambient
B) Cooling the liquid refrigerant below its saturation temperature at condenser
pressure
C) Raising the temperature of the refrigerant after expansion
D) Removing moisture from the refrigerant stream
Exam 200 Que, Exams of Engineering.
SECTION 1: Refrigeration Cycle & Basic Principles (Questions 1-25)
Question 1
What is the primary purpose of a refrigeration system in an air conditioning
setup?
A) Increase indoor humidity
B) Remove heat from a space
C) Circulate air only
D) Generate electricity
Answer: B
Rationale: The primary purpose of a refrigeration system is to remove heat from a
designated space to maintain desired temperatures. This is the fundamental
principle of mechanical refrigeration .
Question 2
In the vapor-compression cycle, which component absorbs heat from the
conditioned space?
,A) Compressor
B) Condenser
C) Expansion valve
D) Evaporator
Answer: D
Rationale: The evaporator allows low-pressure liquid refrigerant to boil and turn
into a gas, absorbing latent heat from the indoor air passing over its coils. This is
where the actual cooling occurs .
Question 3
What is the term for heat that changes the temperature of a substance without
changing its physical state?
A) Latent heat
B) Superheat
C) Subcooling
D) Sensible heat
,Answer: D
Rationale: Sensible heat is the energy added or removed that causes a change in
temperature that can be measured with a thermometer. Latent heat causes
phase changes without temperature change .
Question 4
What is "Latent Heat"?
A) Heat that can be felt on a thermometer
B) Heat required to change the state of a substance without changing
temperature
C) Heat generated by friction in the compressor
D) Heat lost through ductwork
Answer: B
Rationale: Latent heat is "hidden" heat. In HVAC, it is the energy required to
evaporate water or refrigerant, contributing to humidity control. Sensible heat
changes temperature .
Question 5
, The term "Superheat" refers to:
A) The temperature of the refrigerant in the condenser
B) The temperature of the vapor refrigerant above its saturation temperature
C) The temperature of the liquid refrigerant below its saturation point
D) The outdoor ambient temperature plus the heat of compression
Answer: B
Rationale: Superheat is the difference between the actual temperature of the
refrigerant vapor and its saturation temperature at the same pressure. It ensures
no liquid enters the compressor .
Question 6
In a refrigeration system, the term "subcooling" refers to:
A) Reducing the temperature of the suction gas below ambient
B) Cooling the liquid refrigerant below its saturation temperature at condenser
pressure
C) Raising the temperature of the refrigerant after expansion
D) Removing moisture from the refrigerant stream
