Unit that you express for loudness of sound

Options

A. Metre
B. Hertz
C. Decibel
D. Ampere

Answer

To determine the unit used to express the loudness of sound, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Concept of Loudness**: Loudness refers to how we perceive the intensity of sound. It is a subjective measure and can vary from person to person.

2. **Identify the Units of Measurement**: There are various units used in physics to measure different properties. We need to find out which unit is specifically used for loudness.

3. **Evaluate the Options**:
- **Option 1: Meter** - This unit measures distance, not sound.
- **Option 2: Hertz** - This unit measures frequency, which is the number of cycles per second of a sound wave.
- **Option 3: Decibel** - This is a logarithmic unit used to express the intensity of sound. It is commonly used to measure loudness.
- **Option 4: Ampere** - This unit measures electric current, not sound.

4. **Select the Correct Answer**: Based on the evaluation, the correct unit for expressing loudness of sound is **decibel**, represented as dB.

### Final Answer:
The unit that you express for loudness of sound is **decibel (dB)**.

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