The period of a wave is the time the full wave takes to pass a given point. The period, T and the frequency f obey the following relation,
- ,
Since
- ,
Usage of period versus frequency
As a matter of convenience, longer and slower waves, such as ocean waves, tend to be described by period rather than frequency. Short and fast waves, like audio and radio, are usually described by their frequency or wavelength instead of period. These commonly used conversions are listed below:
Frequency: | 1 mHz (10-3) | 1 Hz (100) | 1 kHz (103) | 1 MHz (106) | 1 GHz (109) | 1 THz (1012) |
Period (time): | 10 s (103) | 1 s (100) | 1 ms (10-3) | 1 µs (10-6) | 1 ns (10-9) | 1 ps (10-12) |