Consider the following statements : 1. Steam at 100 C and boiling water at 100 C contain same amount of heat. 2. Latent heat of fusion of ice is equal to the latent heat of vaporization of water. 3. In an air-conditioner, heat is extracted from the room-a

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Q: 22 (IAS/2003)
Consider the following statements :
1. Steam at 100° C and boiling water at 100° C contain same amount of heat.
2. Latent heat of fusion of ice is equal to the latent heat of vaporization of water.
3. In an air-conditioner, heat is extracted from the room-air at the evaporator coils and is rejected out at the condenser coils.
Which of these statements is/are correct?

question_subject: 

Science

question_exam: 

IAS

stats: 

0,21,29,10,16,3,21

keywords: 

{'evaporator coils': [0, 0, 1, 0], 'condenser coils': [0, 0, 1, 0], 'latent heat': [0, 0, 1, 3], 'vaporization': [1, 0, 1, 6], 'boiling water': [0, 0, 2, 1], 'heat': [10, 3, 13, 46], 'steam': [0, 0, 0, 1], 'fusion': [4, 0, 2, 2], 'ice': [0, 0, 1, 0], 'air': [1, 0, 0, 0], 'conditioner': [0, 0, 1, 0]}

In the given question, three statements about heat and temperature are given. The correct answer is option 4 which states that only the third statement is correct. Let`s analyze why.

Statement 1 is incorrect. Steam at 100°C and boiling water at 100°C do not contain the same amount of heat. This is because steam is a gas and has undergone phase change from liquid water, absorbing latent heat in the process, so it contains more heat energy than boiling water at the same temperature.

Statement 2 is also incorrect. The latent heat of fusion (the heat energy required to change a substance from solid to liquid at its melting point) and the latent heat of vaporization (the heat energy required to change a substance from liquid to gas at its boiling point) of water are not equal. The former is typically much less than the latter.

Statement 3 is correct. In an air conditioner, heat is indeed extracted from the room air at the evaporator coils (cooling the room down) and rejected out at the condenser coils (heating the outside environment up). This is the principle that allows air conditioners to cool buildings.