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Whereas a hydrogen atom moves at 1,600 m/s at room temperature and a nitrogen atom moves at 510 m/s, a caesium atom moves at a much slower speed of 130 m/s due to its greater mass. [ 65 ] [ 10 ] The hyperfine frequency of caesium (~9.19 GHz) is also higher than other elements such as rubidium (~6.8 GHz) and hydrogen (~1.4 GHz). [ 10 ]
International Atomic Time (abbreviated TAI, from its French name temps atomique international [1]) is a high-precision atomic coordinate time standard based on the notional passage of proper time on Earth's geoid. [2]
The meaning of the preceding definition is as follows. The caesium atom has a ground state electron state with configuration [Xe] 6s 1 and, consequently, atomic term symbol 2 S 1/2. This means that there is one unpaired electron and the total electron spin of the atom is 1/2. Moreover, the nucleus of caesium-133 has a nuclear spin equal to 7/2.
Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation.
Cuckoo clock, a so-called Jagdstück ("hunt piece"), Black Forest, c. 1900, Deutsches Uhrenmuseum, Inv. 2006-013. A cuckoo clock is a type of clock, not typically pendulum driven, that strikes the hours with a sound like a common cuckoo call and has an automated cuckoo bird that moves with each note.
Teungku Mohammad Daud Beureueh (17 September 1899 – 10 June 1987) was an Indonesian military Governor of Aceh (1945–1953) and leader of the Darul Islam rebellion in the province (1953–1963). Born in the Keumangan chiefdom of Pidie regency, he began in 1930 to champion a more modern form of Islamic school and became a popular reformist ...
Two distinct definitions came into use. Chemists choose to define the AMU as 1 / 16 of the average mass of an oxygen atom as found in nature; that is, the average of the masses of the known isotopes, weighted by their natural abundance. Physicists, on the other hand, defined it as 1 / 16 of the mass of an atom of the isotope ...
The Big Bang theory, which explains the Evolution of the Universe from a hot and dense state, is widely accepted by physicists.. In astronomy, cosmogony is the study of the origin of particular astrophysical objects or systems, and is most commonly used in reference to the origin of the universe, the Solar System, or the Earth–Moon system.