In the following question a statement of assertion (A) is followed by a statement of reason (R )
A : An equipotential surface is normal to electric field lines.
R : Potential increases in direction of electric field .

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 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 false 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
The assertion states: "An equipotential surface is normal to electric field lines."

- **Explanation**: An equipotential surface is defined as a surface where the electric potential is constant. By definition, the electric field lines represent the direction of the force that a positive test charge would experience. Since no work is done when moving a charge along an equipotential surface (as the potential is constant), the electric field must be perpendicular (normal) to the equipotential surfaces. Therefore, this assertion is **correct**.

### Step 2: Understand the Reason
The reason states: "Potential increases in the direction of electric field."

- **Explanation**: The electric field points in the direction of decreasing potential. According to the relationship between electric field (E) and potential (V), we have:
\[ \Delta V = -\int E \cdot dr \]
This indicates that as you move in the direction of the electric field, the potential decreases. Therefore, this reason is **incorrect**.

### Step 3: Conclusion
Since the assertion is correct and the reason is incorrect, we conclude that the correct relationship is:

- Assertion (A) is true.
- Reason (R) is false.

Thus, the answer to the question is that the assertion is true, but the reason is false.

### Final Answer
The assertion is correct, and the reason is incorrect.

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