Loudness of sound increases with

Options

A. The amplitude of vibrating body
B. The increase in surface area of vibrating body
C. The decrease in frequency of vibrating body
D. The increase in distance from the source of sound

Explanation

To solve the question "Loudness of sound increases with," we will analyze each option provided and determine which one is correct.

### Step-by-Step Solution:

1. **Understanding Loudness**:
- Loudness is a subjective perception of sound intensity. It is influenced by various factors, primarily the amplitude of the sound wave.

2. **Analyzing the Options**:
- **Option 1: The amplitude of vibrating body**:
- The amplitude of a sound wave refers to the maximum displacement of particles from their rest position. A larger amplitude means more energy is carried by the sound wave, resulting in a louder sound. Therefore, loudness increases with the amplitude of the vibrating body.

- **Option 2: The increase in surface area of the vibrating body**:
- While a larger surface area can affect how sound is projected, it does not directly correlate with loudness. The loudness is more directly related to amplitude rather than surface area.

- **Option 3: The decrease in frequency of vibrating body**:
- Frequency refers to the number of vibrations per second. Lower frequency sounds are often perceived as deeper or bass sounds, but this does not necessarily mean they are louder. Loudness is primarily related to amplitude rather than frequency.

- **Option 4: The increase in distance from the source of sound**:
- As the distance from the sound source increases, the loudness typically decreases due to the spreading of sound waves over a larger area. Therefore, increasing distance does not increase loudness.

3. **Conclusion**:
- Based on the analysis, the correct answer is **Option 1: The amplitude of vibrating body**. Loudness of sound increases with the amplitude of the vibrating body.

### Final Answer:
Loudness of sound increases with **the amplitude of vibrating body**.

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