Passages

Atomic clocks control timing for

• Satellite communications

• School bells

• Fire Sirens

• Church bells

Atomic clocks for home and office use receive signals from

• Bureau International de l'Heure

• The US Atomic clock

• The Internet

• GPS devices

The first atomic clocks arose from research into

• Clockmaking

• Physics

• Astronomy

• Radio Communications

. The world’s first atomic clock was announced in 1949 by what country?

• United States

• France

• Canada

• Great Britain

How accurate is the current atomic clock?

• Within 1 minute per year

• 1 second every 20 million years

• 1 millionth of a second every 20 years

• 1 second every 20 years

How many atomic clocks are used to standardize world time?