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A heat engine takes in an amount of heat Q1 at temperature T1 and an amount of heat Q2 at temperature T2. If the work output of the engine is J(Q1 + Q2), then this situation

1. breaks the first law of thermodynamics
2. breaks the first law of thermodynamics when Q1 is negative
3. breaks the first law of thermodynamics when Q2 is negative
4. does not break the first law of thermodynamics

Correct answer: does not break the first law of thermodynamics

Solution

If the work output equals the net heat input (Q1+Q2), energy is conserved and the first law of thermodynamics is satisfied; such a process does not break the first law.

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