Practice Course - Practice Course Question 1. Which law of thermo...

Alabama (AL) Licensed HVAC Contractor Practice Course

Question 1. Which law of thermodynamics states that energy cannot be created or destroyed, only transferred or changed in form?

• First Law
• Second Law
• Third Law
• Zeroth Law

Answer: A

Explanation: The First Law of Thermodynamics, also known as the

conservation of energy, states that energy cannot be created or destroyed, only transferred or transformed.

Question 2. Sensible heat is defined as heat that:

• Changes the phase of a substance
• Changes the temperature of a substance without changing its phase
• Is absorbed or released during a phase change
• Is only related to humidity levels

Answer: B 1 / 4

Alabama (AL) Licensed HVAC Contractor Practice Course

Explanation: Sensible heat changes the temperature of a substance without

causing a phase change, unlike latent heat.Question 3. Which principle describes heat transfer through direct contact between materials?

• Conduction
• Convection
• Radiation
• Evaporation

Answer: A

Explanation: Conduction involves heat transfer via direct contact between

molecules of different materials.

Question 4. In psychrometrics, the dew point is:

• The temperature at which air becomes saturated and water vapor

condenses

• The temperature of the air at which sensible heat is maximized
• The temperature where humidity is zero
• The temperature of the refrigerant in the evaporator 2 / 4

Alabama (AL) Licensed HVAC Contractor Practice Course

Answer: A

Explanation: The dew point is the temperature at which air reaches

saturation, causing water vapor to condense into liquid.Question 5. Which refrigerant class is known for having minimal ozone depletion potential but high global warming potential?

• CFCs
• HCFCs
• HFCs
• Natural refrigerants

Answer: C

Answer: C

Explanation: HFCs have little or no ozone depletion potential but can have

high global warming potential.Question 6. The vapor-compression refrigeration cycle primarily involves which component as the compressor?

• Evaporator
• Condenser 3 / 4

Alabama (AL) Licensed HVAC Contractor Practice Course

• Compressor
• Expansion valve

Answer: C

Explanation: The compressor compresses the refrigerant vapor, raising its

pressure and temperature in the cycle.Question 7. Which type of heating system uses water heated in a boiler circulated through pipes to radiate heat?

• Forced air furnace
• Hydronic system
• Heat pump
• Electric resistance heater

Answer: B

Explanation: Hydronic systems utilize water heated in a boiler circulated

through pipes to provide radiant heating.Question 8. What is the primary purpose of a thermostatic expansion valve (TXV) in an HVAC system?

• Increase refrigerant pressure
• / 4