Question

What is the smallest unit of time?

Answer 1

1. The smallest unit of time is $second$.
2. One second is defined as the time taken by the radiation from a cesium-133 atom to complete 9,192,631,770 cycles of oscillations.
3. $$\begin{gathered} 1minute=60seconds \\ 1hour=3600seconds \end{gathered}$$

Hence, second is the smallest fundamental unit of time.