1. What is the main purpose of refrigeration?
A) To increase temperature
B) To remove heat from a space
C) To produce electricity
D) To generate pressure
Right Answer: B) To remove heat from a space
2. Which principle is used in refrigerators to produce cooling?
A) Compression of gas
B) Expansion of liquid
C) Evaporation of liquid refrigerant
D) Condensation of vapor
Right Answer: C) Evaporation of liquid refrigerant
3. Which component compresses the refrigerant in a refrigerator?
A) Condenser
B) Evaporator
C) Compressor
D) Expansion valve
Right Answer: C) Compressor
4. In a refrigerator, the condenser is usually located:
A) Inside the freezer
B) At the back of the unit
C) In the vegetable tray
D) Inside the door
Right Answer: B) At the back of the unit
5. Which refrigerant property is most important for effective cooling?
A) High boiling point
B) Low boiling point
C) High density
D) High viscosity
Right Answer: B) Low boiling point
6. The evaporator in a refrigerator is responsible for:
A) Compressing refrigerant
B) Removing heat from food items
C) Storing refrigerant
D) Producing sound
Right Answer: B) Removing heat from food items
7. Which cycle is commonly used in domestic refrigerators?
A) Carnot cycle
B) Rankine cycle
C) Vapor compression cycle
D) Otto cycle
Right Answer: C) Vapor compression cycle
8. The thermostat in a refrigerator controls:
A) Voltage supply
B) Speed of fan
C) Temperature inside the fridge
D) Size of compressor
Right Answer: C) Temperature inside the fridge
9. Air conditioners mainly work on the principle of:
A) Heat addition
B) Heat removal
C) Combustion
D) Radiation
Right Answer: B) Heat removal
10. Which part of an air conditioner releases heat to the outside air?
A) Evaporator
B) Compressor
C) Condenser
D) Blower
Right Answer: C) Condenser
11. The unit of refrigeration is:
A) Watt
B) Pascal
C) Ton
D) Joule
Right Answer: C) Ton
12. One ton of refrigeration is equal to:
A) Cooling 1 ton of water per hour
B) Melting 1 ton of ice in 24 hours
C) Producing 1000 watts
D) Freezing 1 kg of water
Right Answer: B) Melting 1 ton of ice in 24 hours
13. Which gas is commonly used as refrigerant in modern refrigerators?
A) Oxygen
B) Nitrogen
C) R-134a
D) Carbon dioxide (pure)
Right Answer: C) R-134a
14. The expansion valve in a refrigeration system:
A) Increases pressure
B) Decreases pressure
C) Stores liquid
D) Produces heat
Right Answer: B) Decreases pressure
15. Which process absorbs heat in the refrigeration cycle?
A) Compression
B) Condensation
C) Expansion
D) Evaporation
Right Answer: D) Evaporation
16. Window air conditioners are best suited for:
A) Large factories
B) Single rooms
C) Cars only
D) Cold storage plants
Right Answer: B) Single rooms
17. Split air conditioners consist of:
A) One single unit
B) Three units
C) Indoor and outdoor units
D) Only outdoor unit
Right Answer: C) Indoor and outdoor units
18. The main function of a compressor is to:
A) Reduce temperature
B) Increase refrigerant pressure
C) Absorb heat
D) Remove dust
Right Answer: B) Increase refrigerant pressure
19. Refrigeration slows down food spoilage by:
A) Increasing bacterial growth
B) Decreasing temperature
C) Adding moisture
D) Increasing oxygen
Right Answer: B) Decreasing temperature
20. In air conditioning, humidity control means:
A) Increasing water content always
B) Controlling moisture in air
C) Heating air
D) Compressing air
Right Answer: B) Controlling moisture in air
21. The blower in an air conditioner helps to:
A) Compress gas
B) Circulate air
C) Freeze refrigerant
D) Increase pressure
Right Answer: B) Circulate air
22. CFCs are harmful because they:
A) Increase oxygen
B) Destroy ozone layer
C) Increase rainfall
D) Reduce temperature
Right Answer: B) Destroy ozone layer
23. The freezer compartment is colder because:
A) It has thicker walls
B) Evaporator coils are located there
C) It has no door
D) It contains water
Right Answer: B) Evaporator coils are located there
24. Which device prevents overheating of a compressor?
A) Thermostat
B) Fuse
C) Overload protector
D) Condenser
Right Answer: C) Overload protector
25. The main difference between refrigeration and air conditioning is:
A) Refrigeration cools only liquids
B) Air conditioning controls temperature, humidity and purity
C) Refrigeration uses no compressor
D) Air conditioning uses no refrigerant
Right Answer: B) Air conditioning controls temperature, humidity and purity
26. Which of the following is a natural refrigerant?
A) Ammonia
B) CFC-12
C) R-22
D) R-134a
Right Answer: A) Ammonia
27. In cars, cooling is provided by:
A) Radiator only
B) Car air conditioning system
C) Fan only
D) Battery
Right Answer: B) Car air conditioning system
28. Ice formation on evaporator coils reduces efficiency because:
A) It increases airflow
B) It blocks heat absorption
C) It increases temperature
D) It compresses gas
Right Answer: B) It blocks heat absorption
29. The cooling effect in refrigeration is produced by:
A) Chemical reaction
B) Combustion
C) Absorption of latent heat
D) Radiation only
Right Answer: C) Absorption of latent heat
30. Which factor affects the efficiency of an air conditioner most?
A) Room color
B) Insulation of room
C) Shape of furniture
D) Number of windows only
Right Answer: B) Insulation of room