Compressed air coming out of punctured football becomes cooler because of:
Correct answer: C. Adiabatic expansion
- A. Isothermal expansion
- B. Energy dissipation
- C. Adiabatic expansion
- D. Adiabatic compression
Explanation
The correct answer is Adiabatic expansion. In this process, the air escaping from the punctured football expands rapidly without exchanging heat with the surroundings. The work required for expansion comes from the internal energy of the air, leading to a decrease in temperature. Hence, the air becomes cooler as it exits. Other options are incorrect because: Isothermal expansion would mean the temperature remains constant, Energy dissipation doesn't inherently lead to cooling, and Adiabatic compression would cause an increase in temperature, not a decrease.
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About First Law of Thermodynamics
The first law relates heat supplied, work done and the change in internal energy through energy conservation. Problems use sign conventions and apply the law to isothermal, adiabatic, isobaric and isochoric processes. Internal energy is a state function, while heat and work depend on the path followed.
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