Changes

'''Frequency''' is the [[number]] of occurrences of a repeating [[event]] per unit [[time]]. It is also referred to as [[temporal]] frequency. The period is the duration of one [[cycle]] in a repeating event, so the period is the reciprocal of the frequency.

'''Frequency''' is the [[number]] of occurrences of a repeating [[event]] per unit [[time]]. It is also referred to as [[temporal]] frequency. The period is the duration of one [[cycle]] in a repeating event, so the period is the reciprocal of the frequency.

==Definitions and units==

==Definitions and units==

For cyclical [[processes]], such as [http://en.wikipedia.org/wiki/Rotation rotation], [http://en.wikipedia.org/wiki/Oscillation oscillations], or [[waves]], frequency is defined as a [[number]] of [[cycles]], or periods, 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 a Greek letter ν (nu).

For cyclical [[processes]], such as [https://en.wikipedia.org/wiki/Rotation rotation], [https://en.wikipedia.org/wiki/Oscillation oscillations], or [[waves]], frequency is defined as a [[number]] of [[cycles]], or periods, 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 a Greek letter ν (nu).

In [http://en.wikipedia.org/wiki/SI_derived_unit SI] units, the unit of frequency is hertz (Hz), named after the German physicist Heinrich Hertz. For example, 1 Hz means that an event repeats once per second.

In [https://en.wikipedia.org/wiki/SI_derived_unit SI] units, the unit of frequency is hertz (Hz), named after the German physicist Heinrich Hertz. For example, 1 Hz means that an event repeats once per second.

A [[traditional]] unit of [[measure]] used with rotating [[mechanical]] devices is the revolutions per minute, abbreviated rpm. 60 rpm equals one hertz.[1]

A [[traditional]] unit of [[measure]] used with rotating [[mechanical]] devices is the revolutions per minute, abbreviated rpm. 60 rpm equals one hertz.[1]

The SI unit for period is the second.[http://en.wikipedia.org/wiki/Frequency]

The SI unit for period is the second.[https://en.wikipedia.org/wiki/Frequency]

 

==References==

==References==

* Giancoli, D.C. (1988), Physics for Scientists and Engineers (2nd ed.), Prentice Hall, ISBN 013669201X  

* Giancoli, D.C. (1988), Physics for Scientists and Engineers (2nd ed.), Prentice Hall, ISBN 013669201X  

*Davies, A. (1997). Handbook of Condition Monitoring: Techniques and Methodology. New York: Springer. pp. 275. ISBN 9780412613203. http://books.google.com/books?id=j2mN2aIs2YIC&pg=RA1-PA275.  

*Davies, A. (1997). Handbook of Condition Monitoring: Techniques and Methodology. New York: Springer. pp. 275. ISBN 9780412613203. https://books.google.com/books?id=j2mN2aIs2YIC&pg=RA1-PA275.  

*Bakshi, K.A.; A.V. Bakshi, U.A. Bakshi (2008). Electronic Measurement Systems. US: Technical Publications. pp. 4-14. ISBN 9788184312065. http://books.google.com/books?id=jvnI3Dar3b4C&pg=PT183.  

*Bakshi, K.A.; A.V. Bakshi, U.A. Bakshi (2008). Electronic Measurement Systems. US: Technical Publications. pp. 4-14. ISBN 9788184312065. https://books.google.com/books?id=jvnI3Dar3b4C&pg=PT183.  

*Elert, Glenn; Timothy Condon (2003). "Frequency Range of Dog Hearing" (in English). The Physics Factbook. http://hypertextbook.com/facts/2003/TimCondon.shtml. Retrieved 2008-10-22.  

*Elert, Glenn; Timothy Condon (2003). "Frequency Range of Dog Hearing" (in English). The Physics Factbook. https://hypertextbook.com/facts/2003/TimCondon.shtml. Retrieved 2008-10-22.  

==External links==

==External links==

* [http://inms-ienm.nrc-cnrc.gc.ca/research/optical_frequency_projects_e.html#femtosecond National Research Council of Canada: ''Femtosecond comb; The measurement of optical frequencies'']

* [https://inms-ienm.nrc-cnrc.gc.ca/research/optical_frequency_projects_e.html#femtosecond National Research Council of Canada: ''Femtosecond comb; The measurement of optical frequencies'']

* [http://www.sengpielaudio.com/calculator-wavelength.htm Conversion: frequency to wavelength and back]

* [https://www.sengpielaudio.com/calculator-wavelength.htm Conversion: frequency to wavelength and back]

* [http://www.sengpielaudio.com/calculator-period.htm Conversion: period, cycle duration, periodic time to frequency]

* [https://www.sengpielaudio.com/calculator-period.htm Conversion: period, cycle duration, periodic time to frequency]

* [http://www.sengpielaudio.com/calculator-notenames.htm Keyboard frequencies = naming of notes - The English and American system versus the German system]

* [https://www.sengpielaudio.com/calculator-notenames.htm Keyboard frequencies = naming of notes - The English and American system versus the German system]

* [http://www.acoustics.salford.ac.uk/schools/index1.htm Teaching resource for 14-16yrs on sound including frequency]

* [https://www.acoustics.salford.ac.uk/schools/index1.htm Teaching resource for 14-16yrs on sound including frequency]

* [http://www.ikalogic.com/freq_meter.php A simple tutorial on how to build a frequency meter]

* [https://www.ikalogic.com/freq_meter.php A simple tutorial on how to build a frequency meter]

* [http://www.diracdelta.co.uk/science/source/f/r/frequency/source.html Frequency - diracdelta.co.uk] - [[javascript]] calculation.

* [https://www.diracdelta.co.uk/science/source/f/r/frequency/source.html Frequency - diracdelta.co.uk] - [[javascript]] calculation.

[[Category: Physics]]

[[Category: Physics]]