The length of a second’s pendulum on the surface of earth is 1 m. What will be the length of a second’s pendulum on the moon?
 
A second pendulum is a pendulum with time period (T) = 2 seconds
 
Thus,      …… (i)
Now, 
Thus,         ……. (ii)   (gm=ge/6)
Now, for the second pendulum,
   ……. (since 
)
Thus,