In the following question a statement of assertion (A) is followed by a statement of reason (R )
A : Water has a much greater dielectric constant than any other ordinary subtance.
R : Water has permanent dipole moment .

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 analyze the given statements, we need to evaluate both the assertion (A) and the reason (R) provided in the question.

### Step 1: Understanding the Assertion (A)
The assertion states: "Water has a much greater dielectric constant than any other ordinary substance."

- **Dielectric Constant**: The dielectric constant (also known as relative permittivity) is a measure of a substance's ability to insulate charges from each other. Water has a dielectric constant of approximately 81, which is indeed much higher than that of most other common substances.

### Step 2: Understanding the Reason (R)
The reason states: "Water has a permanent dipole moment."

- **Permanent Dipole Moment**: A permanent dipole moment occurs in molecules that have a significant difference in electronegativity between the atoms involved, leading to an uneven distribution of charge. Water (H₂O) is a polar molecule; the oxygen atom is more electronegative than the hydrogen atoms, resulting in a permanent dipole moment.

### Step 3: Evaluating the Relationship Between A and R
Now we need to determine if the reason (R) correctly explains the assertion (A).

- The high dielectric constant of water is indeed due to its molecular structure and the presence of a permanent dipole moment. The dipole allows water molecules to align in an electric field, which enhances its ability to reduce the effective electric field within the substance.

### Conclusion
Both the assertion (A) and the reason (R) are correct, and the reason provides a valid explanation for the assertion.

### Final Answer
The correct answer is that both the assertion and the reason are correct, and the reason is the correct explanation for the assertion.

---