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Second

The second (symbol: s) is a unit of time derived from the division of the day first into 24 hours, then to 60 minutes, and lastly to 60 seconds each, for a total of 24 × 60 × 60 = 86,400 seconds per day. The current and formal definition in the International System of Units (SI) is more precise: The second [...] is defined by taking the fixed numerical value of the caesium frequency, ΔνCs, the unperturbed ground-state hyperfine transition frequency of the caesium 133 atom, to be 9192631770 when expressed in the unit Hz, which is equal to s−1. That is saying that a second is the duration of time it takes for 9 192 631 770 of these transitions to occur.

Extends: Second

Properties

Property Expected Type Description
Name Text second
Image Text File:Clock-pendulum.gif
Caption Text escapement
Standard Text SI
Quantity Text time
Symbol Text s