Which is true for Internal energy of system is ?

Options

A. State function
B. Path function
C. Both (A) and (B)
D. None of these

Answer

To determine the correct statement regarding the internal energy of a system, we need to analyze the options provided and understand the concept of internal energy in thermodynamics.

### Step-by-Step Solution:

1. **Understanding Internal Energy**:
- Internal energy (U) is defined as the total energy contained within a system. It includes all forms of microscopic energy such as kinetic energy, potential energy, vibrational energy, rotational energy, etc.

2. **Identifying State Function**:
- A state function is a property that depends only on the state of the system and not on the path taken to reach that state. Internal energy is a state function because it is determined by the current state of the system (e.g., temperature, pressure, volume) and does not depend on how the system arrived at that state.

3. **Path Function vs. State Function**:
- Path functions, like work and heat, depend on the specific process or path taken to change the state of the system. In contrast, state functions like internal energy, enthalpy, and entropy are independent of the path taken.

4. **Evaluating the Options**:
- Option A: "Set function" - This seems to be a typographical error and should refer to "state function."
- Option B: "Bath function" - This is not a recognized term in thermodynamics.
- Option C: "Both A and B" - Since B is incorrect, this option cannot be true.
- Option D: "One of these" - This is vague but could imply that only one of the options is correct.

5. **Conclusion**:
- The correct statement regarding the internal energy of the system is that it is a **state function**. Therefore, if we assume option A refers to "state function," then it is the correct answer.

### Final Answer:
The internal energy of a system is a **state function**.

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