A 'jiffy' is an actual unit of time, but it means different
things across various fields of study. The term "jiffy" is often used to describe a very
short but unspecified period of time, for example: "I'll have it sorted
out in a jiffy!" The exact origin of the word is unclear, but it was first
attested in 1785.
Gilbert Newton Lewis (1875–1946) proposed a unit of time
called the "jiffy" which was equal to the time it takes light to
travel one centimeter (approximately 33.3564 picoseconds). Since then, it has
been redefined and used for different measurements in different fields of
study. In electronics, a jiffy is the time between alternating
current power cycles (1/60 or 1/50 of a second). In computing, a jiffy was
originally the time between two ticks of the system timer interrupt. The term
"jiffy" is sometimes used in computer animation as a method of
defining playback rate, with the delay interval between individual frames
specified in 1/100th-of-a-second (10 ms) jiffies.
In astrophysics and quantum physics a jiffy (as defined by
Edward R. Harrison) is, the time it takes for light to travel one fermi, which
is approximately the size of a nucleon. One fermi is10-15 m, so a jiffy is
about 3 × 10-24 seconds. Informally it has been defined as "one
light-foot," which works out as approximately one nanosecond.
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