To describe any sound completely, several physical quantities are required. These quantities provide a comprehensive description of the sound wave. The essential physical quantities needed to describe any sound are:
Amplitude: The amplitude represents the maximum displacement or pressure variation of the sound wave from its equilibrium position. It determines the loudness or intensity of the sound. The unit of amplitude depends on the specific type of sound measurement being used (e.g., pascals for pressure-based measurements or decibels for relative measurements).
Frequency: The frequency of a sound wave represents the number of cycles or vibrations the wave completes per unit of time. It is measured in hertz (Hz). Frequency determines the pitch of the sound, with higher frequencies corresponding to higher-pitched sounds and lower frequencies corresponding to lower-pitched sounds.
Wavelength: The wavelength is the physical distance between two consecutive points of the sound wave that are in phase (e.g., two crests or two troughs). It is typically measured in meters (m). Wavelength is inversely proportional to the frequency of the sound wave.
Phase: The phase describes the position of a point within a sound wave cycle relative to a reference point. It is measured in degrees or radians and provides information about the wave's position in its cycle.
Velocity: The velocity of sound represents the speed at which sound waves propagate through a medium. It depends on the properties of the medium, such as its density, elasticity, and temperature. In dry air at room temperature, the approximate speed of sound is 343 meters per second.
These physical quantities collectively provide a comprehensive description of any sound wave. By specifying the amplitude, frequency, wavelength, phase, and velocity, one can fully characterize a sound wave and its properties.