AC EMPLOYMENT READY
PRACTICE EXAM 100Q
COMPLETE
Question 1: In a vapor-compression air-conditioning system, what occurs in the
evaporator?
Choices:
1) Refrigerant absorbs heat and boils 2) Refrigerant rejects heat and condenses 3) Refrigerant pressure rises without heat transfer 4) Refrigerant is mechanically compressed
Correct Answer: Refrigerant absorbs heat and boils
Explanation: In the evaporator, low-pressure refrigerant absorbs heat from the conditioned air and changes from liquid to vapor.Page 1
Question 2: What is the primary purpose of the compressor in a refrigeration cycle?
Choices:
1) Lower the vapor pressure before the evaporator 2) Raise refrigerant vapor pressure and temperature 3) Meter liquid refrigerant into the evaporator 4) Remove moisture from the liquid line
Correct Answer: Raise refrigerant vapor pressure and temperature
Explanation: The compressor draws in low-pressure vapor and compresses it to a higher pressure and temperature so heat can be rejected at the condenser.
Question 3: Sensible heat is heat that causes which change?
Choices:
1) A change of state only 2) A change in pressure only 3) A measurable temperature change 4) A change in humidity ratio only
Correct Answer: A measurable temperature change
Explanation: Sensible heat changes the temperature of a substance without changing its state.Page 2
Question 4: Latent heat is associated primarily with which process?
Choices:
1) A change in temperature with no phase change 2) A pressure drop through a �lter 3) An increase in motor speed 4) A change of state at essentially constant temperature
Correct Answer: A change of state at essentially constant temperature
Explanation: Latent heat is absorbed or released during a phase change, such as boiling or condensing, without a corresponding temperature change during the phase change.Question 5: A refrigerant enters a condenser as a high-pressure vapor. What should it leave as under normal operation?
Choices:
1) High-pressure liquid 2) Low-pressure vapor 3) Low-pressure liquid-vapor mixture 4) High-pressure superheated vapor only
Correct Answer: High-pressure liquid
Explanation: The condenser rejects heat and condenses high-pressure refrigerant vapor into high-pressure liquid.Page 3