A : The potential energy can be defined only in conservative field.
R : The value of potential energy depends on the reference level (level of zero potential energy).

Options

A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion, then mark (1).
B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion, then mark (2).
C. If Assertion is true statement but Reason is false, then mark (3).
D. If both Assertion and Reason are falsė statements, then mark (4).

Answer

To solve the question, we need to analyze both the assertion (A) and the reason (R) provided.

### Step 1: Understand the Assertion (A)
The assertion states that "The potential energy can be defined only in a conservative field."

- **Explanation**: A conservative field is one where the work done by the forces acting on an object is path-independent and depends only on the initial and final positions. In such fields, potential energy can be defined because it allows us to assign a value to the energy stored due to the position of an object in the field.

### Step 2: Understand the Reason (R)
The reason states that "The value of potential energy depends on the reference level (level of zero potential energy)."

- **Explanation**: Potential energy is relative and is defined with respect to a reference point. For example, if we set the zero potential energy level at ground level, then the potential energy of an object at height \( h \) is given by \( U = mgh \). If we choose a different reference level, the calculated potential energy would change, but the difference in potential energy (which is what affects the work done) remains the same.

### Step 3: Evaluate the Truth of Assertion and Reason
- Both the assertion and the reason are true statements.
- However, the reason does not directly explain why potential energy can only be defined in conservative fields. It merely states a fact about potential energy.

### Conclusion
- The assertion (A) is true because potential energy is indeed defined in conservative fields.
- The reason (R) is also true because potential energy values depend on the reference level chosen.
- However, the reason does not serve as a correct explanation for the assertion.

### Final Answer
Both assertion and reason are true, but the reason is not the correct explanation of the assertion.