Question

A seconds pendulum is taken to a place where acceleration due to gravity falls to one fourth . How is the time period of the pendulum affected, if at all? Give reason. What will be its new time period

Answer 1

g = 1/4 (Time Period is inversely proportional to square root of g)
 
Therefore, T will be doubled. 
Since T of second's pendulum is 2 seconds, the new time will be = (2 x 2) = 4s

Answer 2

see attachment............

so put T1 = 2sec...because it's second pendulum and find T2 = 2× 2 = 4 sec