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Microsecond

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A microsecond is an SI unit of time equal to one millionth (10−6 or 1/1,000,000) of a second. Its symbol is µs. One microsecond is to one second as one second is to 11.574 days.

A microsecond is equal to 1000 nanoseconds or 1/1,000 millisecond. Because the next SI unit is 1000 times larger, measurements of 10−5 and 10−4 seconds are typically expressed as tens or hundreds of microseconds.

Examples

  • 1 microsecond (1 μs) – cycle time for frequency 1 x 106 hertz (1 MHz), the inverse unit. This corresponds to radio wavelength 300 m (AM mediumwave band), as can be calculated by multiplying 1 µs by the speed of light (approximately 3×108 m/s) to determine the distance travelled.
  • 1 microsecond – the length of time of a high-speed, commercial strobe light flash (see air-gap flash).
  • 1.8 microseconds - the amount of time subtracted from the Earth's day as a result of the 2011 Japanese earthquake.
  • 2 microseconds – the lifetime of a muonium particle
  • 2.68 microseconds – the amount of time subtracted from the Earth's day as a result of the 2004 Indian Ocean earthquake.[1]
  • 3.33564095 microseconds – the time taken by light to travel one kilometer in a vacuum
  • 4.63 microseconds – a fifth (a 60th of a 60th of a 60th of a second)
  • 5.4 microseconds – the time taken by light to travel one mile in a vacuum
  • 10 microseconds (μs) – cycle time for frequency 100 kHz, radio wavelength 3 km
  • 17 microseconds: net amount per year that the length of the day lengthens, largely due to tidal acceleration.[citation needed]
  • 20.8 microseconds – sampling interval for digital audio with 48000 samples/s
  • 22.7 microseconds – sampling interval for CD audio (44100 samples/s)
  • 38 microseconds – discrepancy in GPS satellite time per day (compensated by clock speed) due to relativity[2]
  • 50 microseconds – cycle time for highest human-audible tone (20 kHz)
  • 100 microseconds (0.1 ms) – cycle time for frequency 10 kHz
  • 125 microseconds – sampling interval for telephone audio (8000 samples/s)
  • 240 microseconds – half-life of copernicium-277
  • 250 microseconds – cycle time for highest tone in telephone audio (4 kHz)[citation needed]
  • 277.8 microseconds - a fourth (a 60th of a 60th of a second), used in astronomical calculations by al-Biruni and Roger Bacon in 1000 and 1267 AD, respectively.[3][4]

For reference

  • The average human eye blink takes 350 000 microseconds.
  • A camera flash illuminates for 1000 microseconds.
  • Standard camera shutter speed opens the shutter for 4000 microseconds or 4 milliseconds.

See also

References

  1. ^ Buis, Alan (January 10, 2005). "NASA Details Earthquake Effects on the Earth". NASA. Retrieved June 29, 2011.
  2. ^ Richard Pogge. "GPS and Relativity". Retrieved 2011-10-01.
  3. ^
    • 382.1 microseconds - a random number picked by an anonymous contributor
    al-Biruni (1879). The chronology of ancient nations: an English version of the Arabic text of the Athâr-ul-Bâkiya of Albîrûnî, or "Vestiges of the Past". Translated by Sachau C Edward. W.H. Allen. pp. 147–149. OCLC 9986841.
  4. ^ R Bacon (2000) [1928]. The Opus Majus of Roger Bacon. Translated by BR Belle. University of Pennsylvania Press. table facing page 231. ISBN 978-1-85506-856-8. {{cite book}}: Unknown parameter |nopp= ignored (|no-pp= suggested) (help)
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