The cooling of air during its expansion is called:

• A. adiabatic heating
• B. adiabatic cooling
• C. isobaric cooling
• D. isothermal heating

Answer: (B)

Verified step by step guidance

1. Understand the concept of adiabatic processes: These are processes in which no heat is exchanged with the surroundings (Q = 0).
2. Recall that during expansion of a gas without heat exchange (adiabatic expansion), the gas does work on the surroundings, which causes its internal energy to decrease.
3. Since the internal energy of an ideal gas is directly related to its temperature, a decrease in internal energy results in a decrease in temperature.
4. Therefore, when air expands adiabatically, it cools down, which is called adiabatic cooling.
5. Contrast this with other terms: isobaric means constant pressure, isothermal means constant temperature, and heating refers to temperature increase, so the correct term for cooling during expansion without heat exchange is adiabatic cooling.