The unit of amplitude in the context of sound is typically measured in pascals (Pa) or, more commonly, in decibels (dB).
In the case of sound waves, amplitude refers to the maximum displacement of air particles from their resting position as the sound wave propagates. It represents the strength or intensity of the sound wave.
The unit of sound pressure level, which is a measure of the sound intensity, is decibels (dB). The sound pressure level is often expressed relative to a reference level, such as the threshold of human hearing. The dB scale is logarithmic and is calculated using the formula:
L = 20 * log10(P / Pref)
where L is the sound pressure level in decibels, P is the sound pressure of the measured sound wave, and Pref is the reference sound pressure (typically 20 micropascals for the threshold of human hearing).
In addition to sound pressure, other measures of sound amplitude, such as particle velocity and particle displacement, can also be expressed in units of meters per second (m/s) and meters (m), respectively. However, the decibel scale is commonly used to express the intensity or level of sound.