Time
How to say "hodina" in English?
Hour
What year was made first prototype?
1949
What atoms are in atomic clocks?
Cesium 133
How to say "týden" in English?
Week
From what year are used optical clocks?
2000
How much atoms are in atomic clocks?
It's not specific.
How to say "víkend" in English?
Weekend
What year were established cesium clocks?
1990
How many oscilations are there per second?
9 192 631 770/s