Second’s pendulum Aim : To determine the length of second’s pendulum App: metal sphere (bob) , inextensible string , retort stand, meter scale , stop watch, vernier calliper. Formula : Observation: Radius of the bob= 0.9cm , Period of second’s pendulum Ts= 2 sec. Observations for period oscillation T= period Length of second’s pendulum = Result : length of second’s pendulum= L s =103.24 cm