Refrigeration Exam Questions With All Correct Answers Verified Answers 2025 Marking Scheme New Update

Refrigeration Exam Questions With All Correct Answers Verified Answers 2025 Marking Scheme New Update Chapter 1: Basic Physical Principles - Answer- The amount of heat removed to lower the temperature of 15 lbs of water from 48°F to 39°F is: - Answer- 1btu x 15lbs = 15 | 48-39=9 9x15=135 135 BTU A ton of refrigeration is equal to_____Btu/hr - Answer- 12,000 Three states of matter: - Answer- solid, liquid, gas A pressure of 30 ft of water is equal to a pressure of: - Answer- .433 x 30 = 12.99 12.99psig If a pressure gauge reads 5 PSIG at sea level elevation, the corresponding absolute pressure is: - Answer- 5 + 14.7 = 19.7 19.7 psig If the specific volume of a substance is 2.5ft 3/lb, find the weight of a . Of the substance - Answer- 0.4 If the pressure exerted on a refrigerant in the vapor state remains constant, but it's temperature above absolute zero is doubled, the volume of the vapor will be: A. Reduced by 50% B. Unchanged C. Squared D. Approximately doubled - Answer- Approximately doubled When it object is refrigerated: A. Some of its heat energy is destroyed B. Heat is removed from it C. More cooling is added D. It's molecules move faster - Answer- Heat is removed from it When a pound of water is heated from 32°F to 212°F it gains: A. 970 BTU of latent heat B. 144 BTU of latent heat C. 180 BTU of sensible heat D. The heat of fusion - Answer- 180 BTU of sensible heat Absolute zero is calculated to be____°F - Answer- -460°F The unit used to measure the amount of heat removed from a substance is the____. - Answer- BTU The boiling point of a liquid: A. Increases at an elevation above sea level B. Depends on the radiation C. Depends on the absolute pressure D. Depends on the specific heat of the substance - Answer- Depends on the absolute pressure Chapter 2: Elementary Refrigeration Methods - Answer- The low side of a vapor compression cycle contains the: A. Condenser B. Evaporator C. Compressor discharge line D. Condenser and evaporator - Answer- Evaporator A piece of ice weighs 20 Lbs and it's Pacific heat is 0.49. It will require_____Btu to heat the piece of ice from 27°F to 31°F. - Answer- 31 - 27 = 4 4 x 20 = 80 80 x 0.49 = 39.2 39.2 BTUs Of the following terms the largest amount in BTU for 1 pound of water is: A. It's sensible heat B. It's latent heat of fusion C. It's latent heat of vaporization D. It's latent heat of melting - Answer- It's latent heat of vaporization If the evaporator in a vapor compression cycle is not cold enough, it can be made colder by: A. Raising the evaporator pressure B. Stopping the compressor temporarily C. Lowering the evaporator pressure D. Venting the refrigerant to the atmosphere - Answer- Lowering the evaporator pressure Calculate the amount of heat which will be absorbed when 15 pounds of solid substance at a temperature of 30°F is changed to a liquid at 44°F - Answer- The purpose of the condenser in the vapor compression cycle is to: A. Save the refrigerant for reuse B. Reduce the superheated vapor to evaporator temperature C. Reduce the evaporator pressure D. Lower the evaporator temperature - Answer- Save the refrigerant for re-use In the vapor compression cycle, the compressor: A. Heats the refrigerant vapor B. Reduces evaporator pressure C. Compresses the refrigerant vapor. D. All of the above - Answer- Heats the refrigerant vapor Reduces evaporator pressure Compresses the refrigerant vapor. Water can be made to boil at 50°F by: A. Subcooling it to 50°F B. Reducing the pressure to 14.7 psi absolute C. Placing it under a high enough vacuum D. Lowering the pressure to atmospheric pressure - Answer- Placing it under a high enough vacuum Chapter 3: Refrigerants - Answer- An example of a halogen is: A. Sulfur dioxide B. Butane C. Carbon dioxide D. None of these - Answer- None of these List for desirable physical properties of a refrigerant: - Answer- Non-corrosive Chemically Inert Chemically stable Low tendency to leak A fluid: A. Cannot exist in a vapor state B. Can be either a liquid or a solid. C. Must be in the liquid state to be a fluid D. Can be either a liquid or a gas - Answer- Can be either a liquid or a gas Refrigerant HCFC-22 is a: A. Halogenated hydrocarbon B. Halocarbon C. Chlorinated hydrocarbon D. All of the above - Answer- Halogenated hydrocarbon Halocarbon Chlorinated hydrocarbon Ammonia is not used as a refrigerant in air-conditioning systems because: A. It's condensing pressure is too high B. It is relatively unsafe to use C. Low enough temperatures cannot be obtained D. It would freeze at normal evaporator temperatures - Answer- It is relatively unsafe to use