A useful stimulus for testing auditory function is a pure tone for which the sound pressure is a sine wave when plotted against time.
The frequency of a pure tone is the number of cycles or complete oscillations of condensation and rarefaction in one second.
The unit of measurement of frequency is Hertz (Hz). Thus, a pure tone that goes through 1000 cycles per second is said to have a frequency of 1000 Hz, or 1 kHz (kiloHertz).
The period is the time required for one complete cycle, or the time that elapses between two successive condensation or rarefaction peaks.
The wavelength is the distance between two successive peaks on the wave.