Characteristics Of Sound Wave

We can describe a sound wave by its

• frequency
• amplitude and
• speed

A sound wave in graphic form which represents how density and pressure change when the sound wave moves in the medium. The density as well as the pressure of the medium at a given time varies with distance, above and below the average value of density and pressure.

Image (a) Shows the density and image (b) shows the pressure variations as a sound wave propagates in the medium.

Compressions are the regions where particles are crowded together and represented by the upper portion of the curve in image (c).

The peak represents the region of maximum compression. Thus, compressions are regions where density as well as pressure is high. rarefactions are the regions of low pressure where particles are spread apart and are represented by the valley, that is, the lower portion of the curve in image (c). A peak is called the crest and a valley is called the trough of a wave.

The distance between two consecutive compressions (C) or two consecutive rarefactions (R) is called the wavelength. The wavelength is usually represented by λ. Its SI unit is metre (m).