It varies a lot. Everyone has different career and learning schedule so there is not a standard length for completing a phD (for any subjects in general).
My aunt finished her phD in linguistics at U of Connecticut about 15 years ago and it took her 5 years to finish all the courses and essay.
It takes 1 year.
About 88 days
24 hours
It takes 24 hours for one complete cycle.
IT TAKES 243 days.
it takes 1 day
it takes 1 day
The Earth takes approximately 24 hours to complete one full rotation on its axis.
Saturn takes about 10.7 hours to complete one full rotation on its axis.
it takes 9 hours and 56 minutes.
it takes 17 hours and 14 minutes.
It is called a year because it takes that much time to complete one orbit of the sun.