View source for Nanosecond

{{Short description|One billionth of a second}}
{{Infobox unit
| name     = nanosecond
| image    =
| caption  =
| symbol   = ns
| standard = [[SI]]
| quantity = [[time]]
| units1   = [[SI units]]
| inunits1 = {{val|e=-9|ul=s}}
}}
{{wiktionary|nanosecond}}
A '''nanosecond''' ('''ns''') is a unit of [[time]] in the [[International System of Units]] (SI) equal to one billionth of a [[second]], that is, {{sfrac|1|{{val|1000000000}}}} of a second, or {{val|e=−9}} seconds.
The term combines the [[SI prefix]] ''[[nano-]]'' indicating a 1 billionth submultiple of an SI unit (e.g. nanogram, [[nanometre]], etc.) and ''second'', the primary unit of time in the SI.
A nanosecond is to one second, as one second is to approximately 31.69 years.
A nanosecond is equal to 1000&nbsp;[[picosecond]]s or {{sfrac|1|1000}}&nbsp;[[microsecond]].  Time units ranging between 10{{sup|−8}} and 10{{sup|−7}} seconds are typically expressed as tens or hundreds of nanoseconds.
Time units of this granularity are commonly found in [[telecommunications]], pulsed [[laser]]s, and related aspects of [[electronics]].
== Common measurements ==
* 0.001 nanoseconds – one&nbsp;[[picosecond]]
* 0.96 nanoseconds – [[100 Gigabit Ethernet]] [[Interpacket gap]]
* 1.0 nanosecond – cycle time of an electromagnetic wave with a [[frequency]] of 1&nbsp;GHz ({{val|e=9|u=[[hertz]]}}).
* 1.0 nanosecond – electromagnetic [[wavelength]] of 1&nbsp;[[light-nanosecond]]. Equivalent to 0.3&nbsp;m radio band.
* {{val|{{#expr:(1000000000/299792458)*(0.9144/3)}}}}&nbsp;nanoseconds (by [[International yard and pound|definition]]) –  time taken by light to travel 1 [[International yard and pound|foot]] in vacuum.<ref group="n">By definition of the "foot" as exactly 1/3 yards, and of the [[international yard]] as "exactly 0.9144 metres", and of the metre (SI unit) defined by the [[International Bureau of Weights and Measures]] as the "length of the path traveled by light in vacuum during a time interval of 1/{{val|299792458}} of a second". The time taken by light to travel 1 foot in vacuum is therefore (1/299792458) × (0.9144/3) seconds, or {{val|{{#expr:(1000000000/299792458)*(0.9144/3)}}}} nanoseconds.</ref>
* {{val|{{#expr:1000000000/299792458}}}}&nbsp;nanoseconds (by [[Metre#Speed of light definition|definition]]) – time taken by [[light]] to travel 1 [[metre]] in vacuum.<ref name="BIPM21">
{{cite web
|title=Official BIPM definition of the metre
|url=http://www.bipm.org/en/si/si_brochure/chapter2/2-1/metre.html
|publisher=[[BIPM]]
|access-date=2008-09-22
|archive-url=https://web.archive.org/web/20031029003927/http://www.bipm.org/en/si/si_brochure/chapter2/2-1/metre.html
|archive-date=2003-10-29
|url-status=dead
}}</ref>
* 8 nanoseconds – typical [[propagation delay]] of [[7400-series integrated circuits|74HC series logic chips]] based on [[HCMOS]] technology, commonly used for digital electronics in the mid-1980s.<ref>{{cite web|title=74HC-T-U-User-Guide|author=Philips Semiconductors|url=https://www.digikey.fr/htmldatasheets/production/1428461/0/0/1/.pdf |archive-url=https://ghostarchive.org/archive/20221009/https://www.digikey.fr/htmldatasheets/production/1428461/0/0/1/.pdf |archive-date=2022-10-09 |url-status=live}}</ref>
* 10 nanoseconds – one "[[shake (time)|shake]]", (as in a "shake of a lamb's tail") approximate time of one generation of a nuclear chain reaction with fast neutrons
* 10 nanoseconds – cycle time for frequency 100&nbsp;MHz ({{val|e=8|u=[[hertz]]}}), radio wavelength 3&nbsp;[[metre|m]] ([[Radiotelephone|VHF]], [[FM band]])
* 10 nanoseconds – half-life of [[lithium-12]]
* 12 nanoseconds – mean lifetime of a charged [[K meson]]<ref>{{cite web |last=Beringer |first=J. |title=K{{sup|±}} |url=http://pdg.lbl.gov/2012/listings/rpp2012-list-K-plus-minus.pdf |website=pdg.lbl.gov}}</ref>
* 20–40 nanoseconds – time of fusion reaction in a [[hydrogen bomb]]
* 30 nanoseconds – half-life of [[carbon-21]]
* 77 nanoseconds – a sixth (a 60th of a 60th of a 60th of a 60th of a second)
* 96 nanoseconds – [[Gigabit Ethernet]] [[Interpacket gap]]
* 100 nanoseconds – cycle time for [[frequency]] 10&nbsp;MHz, radio wavelength [[1 E1 m|30&nbsp;m]] ([[shortwave]])
* 294.4 nanoseconds – half-life of [[polonium-212]]{{NUBASE2020|ref}}
* 333 nanoseconds – cycle time of highest [[medium wave]] radio frequency, 3&nbsp;MHz
* 500 nanoseconds – T1 time of Josephson [[phase qubit]] (see also ''[[Qubit]]'') as of May 2005
* {{val|1,000}} nanoseconds – one&nbsp;[[microsecond]]
== See also ==
* [[International System of Units]]
* [[Jiffy (time)]]
* [[Microsecond]]
* [[Millisecond]]
* [[Orders of magnitude (time)]]
* [[Picosecond]]
* [[Second]]
== References ==
; Notes :
{{reflist|group="n"}}
; Citations :
{{reflist|1}}
== External links ==
* [https://www.youtube.com/watch?v=9eyFDBPk4Yw Visual representation of a nanosecond] [[Grace Hopper]] explains the nanosecond
{{Orders of magnitude seconds}}
{{DEFAULTSORT:1 E-9 S}}
[[Category:Orders of magnitude (time)]]