It is the time taken to complete one oscilation of the simple pendulum.
It is measured in seconds (s).
If pendulum has brought at position 'A' and then released freely, it passes through 'O' and reaches to B, then returns back and after passing through 'O' reaches at 'A'. In this way pendulum completes one oscilation.
Determination of time period: Calculate the time for ten oscilations with the help of stop watch and then use the following relation to determine the time period.
Time Period = Time taken / number of oscilations
1- Time period of simple pendulum depends only upon its length.