Two pendulum having 2 sec time period,one is on the earth and the other is on the moon having the length ratio of 81:16 .if the value of g on the earth surface 9.81 \( m s^{- 2} \) find the value of g on the moon's surface.

A 1.538 \( m s^{- 2} \)

B \( 1.638 m s^{- 2} \)

C \( 1.938 m s^{- 2} \)