Define a second of time

The second has been defined to be

the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom.

i.e. the time taken by the electron in cesium atom to transfer from one energy band to the other. That's Amazing right.

Most of us don't know what exactly one second of time period refers to and how it is defined ...so here it is.

Now the question lies on how exactly our watches calculate this second. Is it close enough or is it accurate to the nth decimal of a second. But again time is relative.

K@run@