To solve this problem we will start from the given concept in which the number of turns is equivalent to the length of the thread per circumference of spool. That is:
Where,
l = length of the thread
= circumference of spool
For \phi we have that,
For l we have that
l = 62.8m
Finally the number of Turns would be,
Therefore the number of turns of thread on the spool are 1000turns.