Frequency

Frequency is a measure of the number of occurrences of a repeating event per unit of time. It is also referred to as temporal frequency, which emphasizes the contrast to spatial frequency and angular frequency. The period is the duration of time of one cycle in a repeating event, so the period is the reciprocal of the frequency.

Definition and units

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 ν or ν (nu).

Measurement

Common frequency units are:

• Hertz (Hz), cycles per second
• Kilohertz (kHz), thousands of cycles per second
• Megahertz (MHz), millions of cycles per second
• Gigahertz (GHz), billions of cycles per second
• Terahertz (THz), trillions of cycles per second

In Medicine

In medicine, frequency is also a measure of how often a particular event or pattern occurs within a specific timeframe. For example, the frequency of a patient's symptoms, the frequency of a particular disease in a population, or the frequency of a certain medical procedure.

See Also

• Period (physics)
• Wavelength
• Amplitude
• Waveform
• Sound
• Light
• Electromagnetic spectrum

Frequency

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  Frequency
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  Frequency
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  Commutative diagram of harmonic wave properties
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  Resonant reed frequency meter
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  Frequency meter showing 49.9 Hz
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  Frequency counter
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  Electromagnetic spectrum
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  Ultrasound range diagram