Which of the following quantity determines the loudness of a sound wave ? (i) wavelength, (ii) frequency, and (iii) amplitude.

Explanation

To determine which quantity affects the loudness of a sound wave, we can analyze the given options: wavelength, frequency, and amplitude.

### Step-by-Step Solution:

1. **Understanding the Terms**:
- **Wavelength**: This is the distance between two consecutive points in phase on a wave, such as from crest to crest or trough to trough.
- **Frequency**: This refers to the number of cycles of a wave that pass a point in one second, measured in Hertz (Hz).
- **Amplitude**: This is the maximum height of the wave from its mean position (equilibrium position). It indicates the energy of the wave.
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