Question

why the time period of a given simple pendulum is constant?​

Answer 1

Explanation:

A pendulum of given length always takes the same time to complete one oscillation. The time period of a pendulum of given length is constant. Thus, the periodic motion of pendulum has been used to make pendulum clocks for measuring time.

Answer 2

T=2π√l/g

For a given pendulum the length of the string used will be const π and g are also const.

Hence Time period would be const.