Frequency ($\nu =1/T$)

Frequency is the number of repetitions of a periodic phenomenon per unit time. For a wave of period $T$, its frequency is $\nu =1/T$, measured in hertz. The angular frequency is $\omega =2\pi \nu$.

The frequency ratio of two nonzero frequencies is a dimensionless ratio. Ordinary and angular frequencies give the same result because both are converted by the same factor $2\pi$. Rational ratios imply a common period for their sinusoidal motions, while the special ratio two means that one mode completes two cycles during one cycle of the other.

A radio frequency is a frequency in the range used for radio waves. It describes the rapid oscillation of a radio wave, which can differ from the rate at which information is transmitted in radio communication.

The unit of frequency equal to one cycle per second.