Full name: femtosecond
Plural form: femtoseconds
Symbol: fs
Alternate spelling: femtosec
Category type: time
Scale factor: 1.0E-15
The SI base unit for time is the second.
1 second is equal to 1.0E+15 femtoseconds.
Valid units must be of the time type.
You can use this form to select from known units:
The SI prefix "femto" represents a factor of 10-15, or in exponential notation, 1E-15.
So 1 femtosecond = 10-15 arcseconds.
The definition of a second is as follows:
A second of arc or arcsecond is a unit of angular measurement which comprises one-sixtieth of an arcminute, or 1/3600 of a degree of arc or 1/1296000 (approximately 7.7×10-7) of a circle. It is the angular diameter of an object of 1 unit diameter at a distance of 360×60×60/(2pi) (approximately 206,265 units), such as (approximately) 1 cm at 2.1 km, or, directly from the definition, 1 astronomical unit at 1 parsec.