## Period and frequency

- Definition 1: Period
The

**period**of a wave is the time taken by the wave to move one wavelength.

- Definition 2: Frequency
The

**frequency**of a wave is the number of wavelengths per second.

The *period* of a longitudinal wave is the time taken by the wave to move one wavelength. As for transverse waves, the symbol T is used to represent period and period is measured in seconds (s).

The *frequency* f of a wave is the number of wavelengths per second. Using this definition and the fact that the period is the time taken for 1 wavelength, we can define:

$$f=\frac{1}{T}$$(1)

or alternately,

$$T=\frac{1}{f}$$(2)