RETA CERTIFIED ASSISTANT REFRIGERATION OPERATOR (CARO} NEWEST
EVALUATED EXAM PRACTICE 120 QUESTIONS 2026-2027|ORIGINAL
QUESTIONS & ANSWERS |DETAILED RATIONALES |HINTED COMPLETE EXAM
PREP GRADED A+*INSTANT DOWNLOAD PDF*
Question 1
The boiling point of R-717 (ammonia) at atmospheric pressure is:
A) 0°F
B) -18°F
C) -28°F
D) -50°F
ANSWER: C
Ammonia's atmospheric boiling point is -28°F, which is critical for system
charge calculations and understanding its behavior in low-temperature
applications.
Question 2
In a saturated mixture, the quality (x) is defined as the:
A) Mass fraction of liquid
B) Mass fraction of vapor
C) Volume fraction of liquid
D) Temperature difference between phases
ANSWER: B
Quality (x) = mass of vapor ÷ total mass. This thermodynamic property is used
in energy-balance equations for refrigeration cycle analysis.
,Question 3
Which two forms of heat transfer are most common in refrigeration systems?
A) Radiation and convection
B) Conduction and convection
C) Radiation and conduction
D) Advection and radiation
ANSWER: B
Conduction and convection are the dominant heat transfer mechanisms in
refrigeration. Conduction occurs through solid materials (pipe walls), while
convection occurs between fluids and surfaces.
Question 4
A vapor can NOT be:
A) Superheated
B) Saturated
C) Subcooled
D) At a temperature above its boiling point
ANSWER: C
Subcooling is defined as liquid refrigerant at a temperature below its
saturation temperature. By definition, subcooled refrigerant can only exist as a
liquid, not a vapor.
Question 5
,What kind of measurement is a ton of refrigeration?
A) A measure of temperature difference
B) A rate of heat transfer in BTUs per unit of time
C) A measure of refrigerant mass
D) A measure of compressor displacement
ANSWER: B
One ton of refrigeration is defined as 12,000 BTU per hour. It represents the
rate of heat absorption required to melt one ton of ice over a 24-hour period.
Question 6
The latent heat of condensation of a substance is the same as:
A) The sensible heat of the substance
B) The latent heat of evaporation of the substance
C) The specific heat of the substance
D) The superheat of the substance
ANSWER: B
The latent heat of condensation equals the latent heat of evaporation for the
same substance. The energy absorbed during vaporization is released during
condensation.
Question 7
Superheat is found in an air conditioning system in the:
, A) Liquid line
B) Compressor suction line and discharge line
C) Condenser outlet
D) Evaporator inlet
ANSWER: B
Superheated vapor exists after the evaporator (suction line) and after
compression (discharge line). Superheat confirms that refrigerant has fully
vaporized before entering the compressor.
Question 8
Subcooled refrigerant can only be:
A) Vapor
B) Liquid
C) Solid
D) A mixture of liquid and vapor
ANSWER: B
Subcooling refers to liquid refrigerant cooled below its saturation temperature
at a given pressure. Subcooled refrigerant exists only in the liquid phase.
Question 9
Superheated refrigerant can only be:
A) Liquid
B) Vapor
EVALUATED EXAM PRACTICE 120 QUESTIONS 2026-2027|ORIGINAL
QUESTIONS & ANSWERS |DETAILED RATIONALES |HINTED COMPLETE EXAM
PREP GRADED A+*INSTANT DOWNLOAD PDF*
Question 1
The boiling point of R-717 (ammonia) at atmospheric pressure is:
A) 0°F
B) -18°F
C) -28°F
D) -50°F
ANSWER: C
Ammonia's atmospheric boiling point is -28°F, which is critical for system
charge calculations and understanding its behavior in low-temperature
applications.
Question 2
In a saturated mixture, the quality (x) is defined as the:
A) Mass fraction of liquid
B) Mass fraction of vapor
C) Volume fraction of liquid
D) Temperature difference between phases
ANSWER: B
Quality (x) = mass of vapor ÷ total mass. This thermodynamic property is used
in energy-balance equations for refrigeration cycle analysis.
,Question 3
Which two forms of heat transfer are most common in refrigeration systems?
A) Radiation and convection
B) Conduction and convection
C) Radiation and conduction
D) Advection and radiation
ANSWER: B
Conduction and convection are the dominant heat transfer mechanisms in
refrigeration. Conduction occurs through solid materials (pipe walls), while
convection occurs between fluids and surfaces.
Question 4
A vapor can NOT be:
A) Superheated
B) Saturated
C) Subcooled
D) At a temperature above its boiling point
ANSWER: C
Subcooling is defined as liquid refrigerant at a temperature below its
saturation temperature. By definition, subcooled refrigerant can only exist as a
liquid, not a vapor.
Question 5
,What kind of measurement is a ton of refrigeration?
A) A measure of temperature difference
B) A rate of heat transfer in BTUs per unit of time
C) A measure of refrigerant mass
D) A measure of compressor displacement
ANSWER: B
One ton of refrigeration is defined as 12,000 BTU per hour. It represents the
rate of heat absorption required to melt one ton of ice over a 24-hour period.
Question 6
The latent heat of condensation of a substance is the same as:
A) The sensible heat of the substance
B) The latent heat of evaporation of the substance
C) The specific heat of the substance
D) The superheat of the substance
ANSWER: B
The latent heat of condensation equals the latent heat of evaporation for the
same substance. The energy absorbed during vaporization is released during
condensation.
Question 7
Superheat is found in an air conditioning system in the:
, A) Liquid line
B) Compressor suction line and discharge line
C) Condenser outlet
D) Evaporator inlet
ANSWER: B
Superheated vapor exists after the evaporator (suction line) and after
compression (discharge line). Superheat confirms that refrigerant has fully
vaporized before entering the compressor.
Question 8
Subcooled refrigerant can only be:
A) Vapor
B) Liquid
C) Solid
D) A mixture of liquid and vapor
ANSWER: B
Subcooling refers to liquid refrigerant cooled below its saturation temperature
at a given pressure. Subcooled refrigerant exists only in the liquid phase.
Question 9
Superheated refrigerant can only be:
A) Liquid
B) Vapor
