Question

how is second produced?

Answer 1

second (s or sec) ... One second is the time that elapses during 9,192,631,770 (9.192631770 x 10 9 ) cycles of the radiation produced by the transition between two levels of the cesium 133 atom.

Answer 2

Second is the standard International unit of time. 1 second is the time that lapse during 9.1927approx cycles of radiation produced by the transition between two levels of the cesium 133 atoms.