Which correctly represents the entropy (s) of an isolated system during a process.

Options

A.
B.
C.
D.

Answer

To determine which graph correctly represents the entropy (S) of an isolated system during a process, we need to consider the fundamental principles of thermodynamics regarding entropy changes in isolated systems.

### Step-by-Step Solution:

1. **Understanding Entropy in Isolated Systems**:
- An isolated system is one that does not exchange energy or matter with its surroundings. It has a certain amount of entropy, which is a measure of the disorder or randomness in the system.

2. **Entropy Change (ΔS)**:
- For any spontaneous process occurring in an isolated system, the change in entropy (ΔS) must be greater than zero. This means that the entropy of the system must increase over time as the system evolves towards equilibrium.

3. **Equilibrium Condition**:
- At equilibrium, the change in entropy (ΔS) becomes zero. This indicates that the system has reached a state of maximum entropy and no further spontaneous processes can occur.

4. **Analyzing the Graphs**:
- **Graph A**: Shows a decrease in entropy over time, which contradicts the principle that ΔS must be greater than zero for a process to occur.
- **Graph B**: (not mentioned in the transcript but assumed to be present) would need to be analyzed similarly.
- **Graph C**: Shows an increase in entropy over time, which aligns with the principle that for a spontaneous process, ΔS must be greater than zero. It also indicates that at equilibrium, ΔS becomes zero.
- **Graph D**: (not mentioned in the transcript but assumed to be present) would also need to be analyzed similarly.

5. **Conclusion**:
- Based on the analysis, **Graph C** correctly represents the entropy of an isolated system during a process. It shows an increase in entropy until equilibrium is reached, where the entropy change becomes zero.

### Final Answer:
Graph C is the correct representation of the entropy of an isolated system during a process.