The second hand on a clock completes one full rotation every 60 seconds. Therefore, its frequency of rotation is 1/60 Hertz (Hz).

Here's why:

* Frequency is the number of occurrences of a repeating event per unit of time.

* In this case, the "event" is a complete rotation of the second hand.

* The "unit of time" is one second.

So, since the second hand rotates once every 60 seconds, its frequency is 1/60 Hz.