A system undergoes a state change from 1 to 2. According the second law of thermodynamics for the process to be feasible, the entropy change, S2-S1 of the system
- A. is positive or zero
- B. is negative or zero
- C. is zero
- D. can be positive, negative or zero
Answer: D. can be positive, negative or zero
Explanation: The entropy of the *system* can decrease (if heat is lost). It is the entropy of the *universe* (System + Surroundings) that must be >= 0.