Which of the following best describes rarefraction?

Rarefraction refers to areas within a wave where the pressure is lower than in the surrounding areas, specifically in the context of sound waves. In a longitudinal wave, which is the type of wave sound travels through, particles of the medium oscillate back and forth in the direction of the wave propagation. During the rarefaction phase, these particles are further apart, leading to a decrease in pressure compared to areas where the particles are more closely packed.

This concept is fundamental to understanding sound wave propagation, as sound is characterized by alternating regions of compression (where particles are closer together and pressure is higher) and rarefraction. Recognizing these areas is crucial for audio professionals, particularly in acoustics and hearing instrument fitting, as they play a key role in how sound is perceived by the human ear.