Frequency rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio signals (sound), radio waves, and light. For cyclical processes, such as rotation, oscillations, or waves, frequency is defined as a number of cycles per unit time. In physics and engineering disciplines, such as optics, acoustics, and radio, frequency is usually denoted by a Latin letter "f" or by the Greek letter "formula_1" or "ν" (nu) (see e.g. Planck's formula). The relation between the frequency and the period formula_2of a repeating event or oscillation is given by The SI derived unit of frequency is the hertz (Hz), named after the
Maxwell (unit) non-SI unit. That is, one maxwell is the total flux across a surface of one square centimetre perpendicular to a magnetic field of strength one gauss. The weber is the related SI unit of magnetic flux, which was defined in 1946. Maxwell (unit) The maxwell (symbol: Mx) is the CGS (centimetre-gram-second) unit of magnetic flux (). The unit name honours James Clerk Maxwell, who presented a unified theory of electromagnetism. The "maxwell" was recommended as a CGS unit at the International Electrical Congress held in 1900 at Paris. This practical unit was previously called a "line", reflecting Faraday's conception of