Frequency: Difference between revisions
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imported>John R. Brews (link) |
imported>Mark Widmer (Added relation to period. Clarified where discussion is specific to wave phenomena.) |
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'''Frequency''' is a property of an [[oscillation]], [[Vibrational spectrum|vibration]], or other regularly-repeating (cyclic) phenomenon. The frequency of such a phenomenon is the number of repetitions (cycles) in a unit of [[time]]. In the [[SI]] system of units, frequency is measured in [[Hertz]] ('''Hz'''), the number of repetitions in one [[second]]. | '''Frequency''' is a property of an [[oscillation]], [[Vibrational spectrum|vibration]], or other regularly-repeating (cyclic) phenomenon. The frequency of such a phenomenon is the number of repetitions (cycles) in a unit of [[time]]. In the [[SI]] system of units, frequency is measured in [[Hertz]] ('''Hz'''), the number of repetitions in one [[second]]. | ||
Frequency ( '''''f''''' ) is the reciprocal of the period ( '''''T''''' ), which is the time interval over which the phenomenon repeats: | |||
:<math>\lambda = \frac{c}{f} \,\!</math>, where '''''c''''' is the speed of propagation of | :<math>{f} = \frac{1}{T} \,\!</math> | ||
For a wave propagating through space, frequency ( '''''f''''' ) is inversely proportional to [[wavelength]] ( '''''λ''''' ), which is a length measurement: | |||
:<math>\lambda = \frac{c}{f} \,\!</math>, where '''''c''''' is the speed of propagation of the wave. For [[electromagnetic radiation]] in a vacuum, '''''c''''' = 299 792 458 m/s, the [[speed of light]]. | |||
In electromagnetic radiation, the [[energy]] of the vibration is proportional to the frequency: | In electromagnetic radiation, the [[energy]] of the vibration is proportional to the frequency: | ||
:<math>E=hf \,\!</math> , where '''''h''''' = 6.626 x 10<sup>-34</sup> J•s ([[Planck's constant]]) | :<math>E=hf \,\!</math> , where '''''h''''' = 6.626 x 10<sup>-34</sup> J•s ([[Planck's constant]]) | ||
Revision as of 18:57, 21 July 2020
Frequency is a property of an oscillation, vibration, or other regularly-repeating (cyclic) phenomenon. The frequency of such a phenomenon is the number of repetitions (cycles) in a unit of time. In the SI system of units, frequency is measured in Hertz (Hz), the number of repetitions in one second.
Frequency ( f ) is the reciprocal of the period ( T ), which is the time interval over which the phenomenon repeats:
For a wave propagating through space, frequency ( f ) is inversely proportional to wavelength ( λ ), which is a length measurement:
- , where c is the speed of propagation of the wave. For electromagnetic radiation in a vacuum, c = 299 792 458 m/s, the speed of light.
In electromagnetic radiation, the energy of the vibration is proportional to the frequency:
- , where h = 6.626 x 10-34 J•s (Planck's constant)
