<P> 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, particularly in Autodesk Animator . FLI sequences (one global frame frequency setting) and animated Compuserve . GIF images (each frame having an individually defined display time measured in 1 / 100 s). </P> <P> The speed of light in a vacuum provides a convenient universal relationship between distance and time, so in physics (particularly in quantum physics) and often in chemistry, a jiffy is defined as the time taken for light to travel some specified distance . In astrophysics and quantum physics a jiffy is, as defined by Edward R. Harrison, the time it takes for light to travel one fermi, which is approximately the size of a nucleon . One fermi is 10 m, so a jiffy is about 3 × 10 seconds . It has also more informally been defined as "one light - foot", which is equal to approximately one nanosecond . </P> <P> One author has used the word jiffy to denote the Planck time of about 5.4 × 10 seconds, which is the time it would take light to travel a Planck length if ordinary geometry were still relevant at that scale . </P>

Where does the phrase in a jiffy come from