A simple pendulum of length 'L1' has a time period 'T1' and another pendulum of length 'L2' has time period 'T2'. Then the time period of pendulum of length (L1+L2) is

time period of a simple pendulum is T1=2πl1g T2=2πl2g      ⇒T12αl1----(1)      ⇒ T22αl2----(2)     T=2πl1+l2g  ⇒T2αl1+l2----(3) substitute (1),(2) in (3)         T2αT12+T22    ⇒TαT12+T22