Question

A refrigerator is a device which works on the principle that evaporation of a liquid gives a cooling effect.
A. True
B. False

Answer 1

Hint: Refrigerator is a device used for refrigeration i.e. to maintain the temperature of the system lower as compared to surrounding. The working principle of a refrigerator involves the removal of heat from one region and its deposition to another. It works by passing a cool refrigerant around the food items which are kept inside the refrigerator. This refrigerant then absorbs heat from the food items and then loses that heat to a relatively cooler surrounding on the outside.

Complete answer:
A refrigerator works on the principle of the second law of thermodynamics. This law is related to the extraction of heat from a body i.e. to lower the temperature of the body. The temperature of the body can be lowered by extracting or removing the heat from the material or the body. This phenomenon takes place in refrigerators as well. Coolant flowing through coolant tubes and condensers play a very important role in extracting heat from all the items kept in the refrigerator. The evaporator in the refrigerator is the part that makes the items in the refrigerator cold. Refrigerant turns from a liquid to gas through evaporation and the evaporator cools the area around it. Thus, producing a proper environment for storing food.
Hence, a refrigerator is a device which works on the principle that evaporation of a liquid gives a cooling effect.

So, the correct answer is option A i.e. True.

Note:
Students must remember that the refrigerators and air-conditioners both work on the principle of cooling through evaporation of a liquid. Refrigerators, air conditioners and all the other cooling devices use HFC-134a gas for cooling purposes. But when this gas is released in the atmosphere, it damages the ozone layer in the atmosphere which is also harmful for human beings. Scientists are looking for an alternative to this gas.