For an adiabatic compression W=100J, what will be ∆U?
Correct answer: C. +100 J
- A. -100 J
- B. 0 J
- C. +100 J
- D. None
Explanation
In an adiabatic process, there is no heat exchange with the surroundings (Q = 0). According to the First Law of Thermodynamics, the change in internal energy (∆U) is given by ∆U = Q - W. Since Q = 0, the equation simplifies to ∆U = -W. During adiabatic compression, work is done on the system, and W = -100 J (since work done on the system is positive), leading to ∆U = +100 J. Therefore, the correct answer is Option C. Other options are incorrect because they do not account for the increase in internal energy due to the positive work done on the system.
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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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