Assertion: Surface waves are neither transverse nor longitudinal.
Reason: In surface wave particles undergo circular motion.

Options

A. If both Assertion and Reason are true and the Reason is correct expanation of the Assertion.
B. If both Assertion and Reason are true but the Reason is not correct expanation of the Assertion.
C. If Assertion is true, but the Reason is false.
D. If Assertion is false but the Reason is true.

Answer

To solve the assertion-reason question, we will analyze both the assertion and the reason step by step.

### Step 1: Analyze the Assertion
**Assertion**: Surface waves are neither transverse nor longitudinal.

- Surface waves, such as those seen on the surface of water, exhibit characteristics of both transverse and longitudinal waves. In a transverse wave, particles move perpendicular to the direction of wave propagation, while in a longitudinal wave, particles move parallel to the direction of wave propagation.
- Surface waves involve a combination of these motions, where particles move in circular or elliptical paths. Therefore, the assertion that surface waves are neither transverse nor longitudinal is misleading.

### Step 2: Analyze the Reason
**Reason**: In surface waves, particles undergo circular motion.

- This statement is true. In surface waves, particularly in water waves, particles at the surface move in circular paths as the wave passes. This circular motion is a result of the combination of the up-and-down motion (transverse) and the back-and-forth motion (longitudinal) of the particles.
- While the reason correctly describes the behavior of particles in surface waves, it does not adequately explain why surface waves are classified as neither transverse nor longitudinal.

### Conclusion
- Both the assertion and the reason are true statements. However, the reason does not serve as a correct explanation for the assertion. Therefore, the correct answer is that the assertion is false, and the reason is true, but it does not explain the assertion.

### Final Answer
- The assertion is incorrect, and the reason is correct but does not explain the assertion. Hence, the correct option is B.