Which of the following statement is not true ?

Options

A. Electrostatic force is a conservative force
B. Potential energy of charge q at a point is the work done per unit charge in bringing a charge from any point to infinity
C. Spring force and gravitational force are conservative force
D. Both (a) and ( c)

Answer

To determine which statement is not true among the given options, we need to analyze each statement carefully.

### Step-by-Step Solution:

1. **Statement Analysis**:
- **Statement 1**: "Electrostatic force is a conservative force."
- This statement is true. Electrostatic forces do not depend on the path taken; they depend only on the initial and final positions. Therefore, the work done by electrostatic forces is independent of the path, confirming that it is a conservative force.

2. **Statement 2**: "Potential energy of a charge Q at a point is the work done per unit charge in bringing a charge from any point to infinity."
- This statement is misleading. The correct definition states that the potential energy of a charge at a point is the work done per unit charge in bringing a charge from infinity to that point, not the other way around. Therefore, this statement is **not true**.

3. **Statement 3**: "Spring force and gravitational force are conservative forces."
- This statement is true. Both spring force and gravitational force are conservative forces because the work done by these forces only depends on the initial and final positions, not on the path taken.

4. **Statement 4**: "Both A and C."
- Since both Statement 1 and Statement 3 are true, this statement is also true.

5. **Conclusion**:
- The only statement that is not true is Statement 2. Therefore, the answer to the question is **Statement 2**.

### Final Answer:
The statement that is not true is: **"Potential energy of a charge Q at a point is the work done per unit charge in bringing a charge from any point to infinity."**

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