# Nanosecond

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A **nanosecond** (**ns**) is an SI unit of time equal to one thousand-millionth of a second (or one billionth of a second), that is, ^{1}/_{1,000,000,000} of a second, or 10^{−9} seconds.

The term combines the prefix *nano-* with the basic unit for one-sixtieth of a minute.

A nanosecond is equal to 1000 picoseconds or ^{1}⁄_{1000} microsecond. Time units ranging between 10^{−8} and 10^{−7} seconds are typically expressed as tens or hundreds of nanoseconds.

Time units of this granularity are commonly encountered in telecommunications, pulsed lasers, and related aspects of electronics.

## Common measurementsEdit

- 0.5 nanoseconds – the half-life of beryllium-13.
- 0.96 nanoseconds – 100 Gigabit Ethernet Interpacket gap
- 1.0 nanosecond – cycle time of an electromagnetic wave with a frequency of 1 GHz (1×10
^{9}hertz). - 1.0 nanosecond – electromagnetic wavelength of 1 light-nanosecond. Equivalent to 0.3m radio band.
- 1.016703362164 nanoseconds (by definition) – time taken by light to travel 1 foot in a vacuum.
^{[n 1]} - 1.1 nanoseconds – a commonly-used rough definition of a "light-foot".
^{cf. }^{[1]}^{[2]} - 3.3356409519815 nanoseconds (by definition) – time taken by light to travel 1 metre in a vacuum.
^{[3]} - 10 nanoseconds – one "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 MHz (1×10
^{8}hertz), radio wavelength 3 m (VHF, FM band) - 12 nanoseconds – mean lifetime of a K meson
^{[4]} - 10 nanoseconds – half-life of lithium-12
- 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 MHz, radio wavelength 30 m (shortwave)
- 299 nanoseconds – half-life of polonium-212
- 333 nanoseconds – cycle time of highest medium wave radio frequency, 3 MHz
- 500 nanoseconds – T1 time of Josephson phase qubit (see also Qubit) as of May 2005
- 1,000 nanoseconds – one microsecond
- 1,000,000 nanoseconds – one milisecond (ms)

## See alsoEdit

## ReferencesEdit

- Notes

**^**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 1/299792458 of a second". The time taken by light to travel 1 foot in a vacuum is therefore (1/299792458)x(0.9144/3) seconds, or 1.016703362164 nanoseconds.

- Citations

**^**David Mermin (2009).*It's About Time: Understanding Einstein's Relativity*. Princeton, New Jersey: Princeton University Press. p. 22. ISBN 978-0-691-14127-5.**^**Gamow, George (1961),*One, Two, Three... Infinity: Facts & Speculations of Science*(3rd ed.), Courier Dover Publications, p. 77, ISBN 0486256642.**^**"Official BIPM definition of the metre". BIPM. Retrieved 2008-09-22.**^***http://pdg.lbl.gov/2012/listings/rpp2012-list-K-plus-minus.pdf*. Missing or empty`|title=`

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