Assertion (A) : The thickest string in a musical instruments gives the highest noise.
Reason (R): It vibrates slowly

Options

A. Both A and R are true and R is the correct explanation of A.
B. Both A and R are true but R is not the correct explanation of A.
C. A is true but R is false.
D. A is false but R is true.

Explanation

To solve the question, we need to analyze both the assertion and the reason provided.

### Step-by-Step Solution:

1. **Understanding the Assertion (A)**:
- The assertion states that "The thickest string in a musical instrument gives the highest noise."
- We need to determine if this statement is true or false.

2. **Analyzing the Reason (R)**:
- The reason states that "It vibrates slowly."
- We need to understand how the thickness of a string affects its vibration and sound production.

3. **Effect of Thickness on Mass per Unit Length**:
- A thicker string has a greater mass per unit length compared to a thinner string of the same length.
- This means that as the thickness increases, the mass of the string increases.

4. **Impact on Sound Velocity**:
- The speed of sound in a string is inversely related to the mass per unit length.
- Therefore, if the mass per unit length is greater (due to increased thickness), the speed of sound in that string will be lower.

5. **Relationship Between Speed, Wavelength, and Frequency**:
- The speed of sound (v) in a string can be expressed as:
\[ v = \lambda \times f \]
where \( \lambda \) is the wavelength and \( f \) is the frequency.
- If the speed (v) is lower, and assuming the wavelength remains constant, the frequency (f) must also be lower.

6. **Conclusion on Noise Production**:
- A lower frequency corresponds to a lower pitch sound, which means that a thicker string produces lower noise (or sound) compared to a thinner string.
- Therefore, the assertion that "the thickest string gives the highest noise" is **false**.

7. **Evaluating the Reason**:
- The reason states that the thickest string vibrates slowly, which is true because of the increased mass per unit length.
- Thus, while the reason is correct, it does not support the assertion.

8. **Final Evaluation**:
- Since the assertion (A) is false and the reason (R) is true, we conclude that:
- **Assertion (A) is false, Reason (R) is true**.

### Final Answer:
- The correct option is: **A is false but R is true**.