Briefly trace the history of the atomic clock from 1940 until 1991.

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Explanation:

1945 — Isidor Rabi, a physics professor at Columbia University, suggests a clock could be made from a technique he developed in the 1930’s called atomic beam magnetic resonance. 1949 — Using Rabi’s technique, NIST (then the National Bureau of Standards) announces the world’s first atomic clock using the ammonia molecule as the source of vibrations.

your answer would be (a)

the virginia plan called for three branches of government and two houses of congress. representation in each house would be determined by population. the new jersey plan called for three branches of government and a single house of congress. each state would have an equal vote.