Compressed air coming out of punctured football becomes cooler because of:
Correct answer: C. Adiabatic expansion
- A. Isothermal expansion
- B. Energy dissipiation
- C. Adiabatic expansion
- D. Adiabatic compression
Explanation
Adiabatic expansion is a type of expansion in which no heat is exchanged with the surroundings. This means that the only way for the gas to lose energy is by doing work. When the air expands through the small hole in the football, it does work by accelerating. This work comes from the internal energy of the air, which is what causes the air to cool.
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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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