# Difference between revisions of "Frequency"

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imported>Anthony Argyriou (clarify frequency/wavelength relationship and frequency/energy relationship) |
imported>Milton Beychok m (Copy edits) |
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'''Frequency''' is a property of an oscillation, [[vibration]], or other regularly-repeating phenomenon. The frequency of such a phenomenon is the number of repetitions in a unit [[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]], [[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]]. | ||

The frequency of vibrations is inversely proportional to [[wavelength]], which is a length measurement | The frequency ( '''''f''''' ) of vibrations 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 waves in the medium, or, for [[electromagnetic radiation]], c = 299 792 458 m/s, the [[speed of light]]. | |||

:<math>\lambda = \frac{c}{f} \,\!</math>, where '''''c''''' is the speed of propagation of waves in the medium, or, for [[electromagnetic radiation]], '''''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 14:46, 8 March 2010

**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.

The frequency ( * f* ) of vibrations is inversely proportional to wavelength (

*), which is a length measurement:*

**λ**- , where
is the speed of propagation of waves in the medium, or, for electromagnetic radiation,**c**= 299 792 458 m/s, the speed of light.**c**

In electromagnetic radiation, the energy of the vibration is proportional to the frequency:

- , where
= 6.626 x 10**h**^{-34}J•s (Planck's constant)