Which of the following is necessarily zero when the system is a ideal gas that undergoes a change at a constant temperature?
Correct answer: C. Change in internal energy
- A. Work
- B. Pressure
- C. Change in internal energy
- D. None of these
Explanation
In the context of an ideal gas undergoing a process at constant temperature, the internal energy of the gas is only a function of its temperature. Since the temperature remains unchanged, there is no change in the internal energy of the system, making the change in internal energy zero. Work and pressure are not necessarily zero because work can be done by or on the system if there's a change in volume, and pressure can vary with changes in volume. Therefore, the correct answer is the change in internal energy.
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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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