Which of the following statements is correct?

Options

A. All vibrations produce sound.
B. Vibrations of frequency more than 20 Hz only produce sound.
C. Vibrations of frequency between 20 Hz and 20,000 Hz only produce sound.
D. Vibrations of frequency between 20 Hz and 20,000 Hz only produce sound.

Explanation

To determine which statement is correct regarding sound and vibrations, we can analyze the options given based on our understanding of sound waves and their characteristics.

### Step-by-Step Solution:

1. **Understanding Sound Production**:
- Sound is produced by vibrations. When an object vibrates, it causes the surrounding medium (like air, water, or solids) to vibrate as well, creating sound waves.

2. **Frequency Range of Sound**:
- The human ear can typically hear sounds in the frequency range of 20 Hz to 20,000 Hz (20 kHz).
- Frequencies below 20 Hz are termed infrasonic, and those above 20 kHz are ultrasonic.

3. **Analyzing the Statements**:
- **Statement 1**: "All vibrations produce sound."
- This is true because any vibration can create sound waves, regardless of frequency. However, we may not hear all sounds.
- **Statement 2**: "Vibrations of frequency more than 20 Hz only produce sound."
- This is misleading. While sounds above 20 Hz are audible, vibrations below this frequency can still produce sound, but it may not be heard by humans.
- **Statement 3**: "Vibrations of frequency between 20 Hz and 20,000 Hz only produce sound."
- This statement is also misleading. While this frequency range is where humans can hear sound, vibrations outside this range can still produce sound, just not in the audible range for humans.
- **Statement 4**: "Vibrations of frequency between 20 Hz and 20,000 Hz only produce sound."
- This is a repeat of the previous statement and is equally misleading.

4. **Conclusion**:
- The correct statement is: "All vibrations produce sound." This encompasses all frequencies, including those that are infrasonic (below 20 Hz) and ultrasonic (above 20 kHz), even if they are not audible to the human ear.

### Final Answer:
The correct statement is: **All vibrations produce sound.**