Physics - Sound (Production, Propagation, Amplitude, Pitch)

Sound is a form of energy produced by mechanical vibrations of an object. These vibrations are transmitted through a medium as longitudinal waves.

Sound requires a material medium (solid, liquid, or gas) for propagation and cannot travel through a vacuum ($0 \text{ m/s}$).

The speed of sound depends on the nature of the medium. Generally, $v_{\text{solids}} > v_{\text{liquids}} > v_{\text{gases}}$. In air, the speed is approximately $330 \text{ m/s}$ to $340 \text{ m/s}$.

Amplitude ($A$) is the maximum displacement of a vibrating particle from its mean position. It determines the loudness of sound; $Loudness \propto (Amplitude)^2$.

Frequency ($f$) is the number of vibrations per second, measured in Hertz ($Hz$). It determines the pitch (shrilness) of the sound.

Time Period ($T$) is the time taken by a vibrating body to complete one full vibration, measured in seconds ($s$).

The human audible range is between $20 \text{ Hz}$ and $20,000 \text{ Hz}$. Sounds below $20 \text{ Hz}$ are infrasonic, and above $20,000 \text{ Hz}$ are ultrasonic.