For an adiabatic compression W=100J, what will be ∆U?
Correct answer: C. +100 J
- A. -100J
- B. 0 J
- C. +100 J
- D. None
Explanation
The correct answer is C because in an adiabatic process, there is no heat exchange (Q = 0) between the gas and its surroundings. The work done on the gas during the adiabatic compression is given as W = 100 J. According to the First Law of Thermodynamics, ∆U = Q - W, where ∆U is the change in internal energy, Q is the heat exchange, and W is the work done on the system. Since the process is adiabatic (Q = 0), the change in internal energy (∆U) is equal to the work done (W) on the system, which is 100 J. Therefore, the correct answer is C, +100 J.
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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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