When you apply the first law of thermodynamics to an ideal heat engine, which of the following parameters are set correctly for one complete cycle?Multiple select question.ΔU > 0W < QW = QΔU = 0
Question
When you apply the first law of thermodynamics to an ideal heat engine, which of the following parameters are set correctly for one complete cycle?Multiple select question.ΔU > 0W < QW = QΔU = 0
Solution
The first law of thermodynamics states that the change in internal energy of a system (ΔU) is equal to the heat added to the system (Q) minus the work done by the system (W). In a complete cycle of an ideal heat engine, the system returns to its initial state, so the change in internal energy (ΔU) is zero. Therefore, ΔU = 0 is correct.
The work done by the system (W) is less than the heat added to the system (Q) because some of the heat is used to increase the internal energy of the system. Therefore, W < Q is correct.
W = Q is incorrect because, as mentioned above, some of the heat is used to increase the internal energy of the system.
ΔU > 0 is incorrect because, in a complete cycle, the system returns to its initial state, so the change in internal energy is zero, not greater than zero.
So, the correct parameters for one complete cycle when applying the first law of thermodynamics to an ideal heat engine are ΔU = 0 and W < Q.
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