Which of the following statements concerning thermodynamic processes is strictly correct for a cyclic process executed by an ideal gas system?

💡 Solution & Explanation

Internal energy is a state function, meaning its value depends only on the current state of the system and not on the path taken. In any complete cyclic process, the system returns to its initial state, making the net change in internal energy zero. The first law of thermodynamics then implies that the net heat added to the system equals the net work done by it over the cycle. Violating the Kelvin-Planck statement prevents complete conversion of heat into work without other thermal reservoirs.