SOUND
SOUND.
Sound is an important example of a longitudinal wave which is composed of both compressions and rarefactions. The frequency range in which compressional disturbances occur is called the sonic spectrum and is very large.
Sound is a range of compressional wave frequencies sensitive to human ear and is known as audio range which ranges from 20 Hz to 20,000 Hz.
Compressional waves with frequencies above and below the audio range are called ultrasonic and infrasonic frequencies respectively.