AP Psychology Practice Test

The frequency of a sound wave is a critical factor in determining its pitch. In the context of sound waves, frequency refers to the number of cycles that occur in a second, measured in hertz (Hz). Higher frequency sound waves correspond to higher pitches, which are perceived as sounds that are "higher" in tone, such as a flute playing a high note. Conversely, lower frequency sound waves are associated with lower pitches, such as the deep sound of a bass drum.

Understanding this relationship is essential, as it highlights how our auditory system interprets different frequencies as varying pitches. For instance, a sound wave with a frequency of 440 Hz is perceived as the note A above middle C, which is a commonly referenced pitch in music.

The other choices relate to different characteristics of sound waves: amplitude is associated with the loudness or intensity of the sound; velocity pertains to the speed at which sound travels through a medium; and intensity refers to the power or strength of the sound signal, which also relates to amplitude but is distinct from pitch. Thus, each of these factors contributes to our perception of sound but does not directly determine its pitch like frequency does.