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This is a list of radioactive nuclides (sometimes also called isotopes), ordered by half-life from shortest to longest, in seconds, minutes, hours, days and years. Current methods make it difficult to measure half-lives between approximately 10 −19 and 10 −10 seconds.
single seconds (1 das = 10 s) 6 das: One minute (min), the time it takes a second hand to cycle around a clock face 10 2: hectosecond hs minutes (1 hs = 1 min 40 s = 100 s) 2 hs (3 min 20 s): The average length of the most popular YouTube videos as of January 2017 [15] 5.55 hs (9 min 12 s): The longest videos in the above study
Sample of cobalt-60 that emits 1 μCi (microcurie) of radioactivity; i.e. 37,000 decays per second. The curie (symbol Ci ) is a non- SI unit of radioactivity originally defined in 1910. According to a notice in Nature at the time, it was to be named in honour of Pierre Curie , [ 1 ] but was considered at least by some to be in honour of Marie ...
The hertz is defined as one per second for periodic events. The International Committee for Weights and Measures defined the second as "the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom" [3] [4] and then adds: "It follows that the hyperfine splitting in the ground state of the ...
A pendulum with a period of 2.8 s and a frequency of 0.36 Hz. For cyclical phenomena such as oscillations, waves, or for examples of simple harmonic motion, the term frequency is defined as the number of cycles or repetitions per unit of time.
Although the length of a moment in modern seconds was therefore not fixed, on average, a medieval moment corresponded to 90 seconds. A solar day can be divided into 24 hours of either equal or unequal lengths, [ 2 ] [ 3 ] the former being called natural or equinoctial, and the latter artificial.
A femtosecond is a unit of time in the International System of Units (SI) equal to 10 −15 or 1 ⁄ 1 000 000 000 000 000 of a second; that is, one quadrillionth, or one millionth of one billionth, of a second. [1] A femtosecond is to a second, as a second is to approximately 31.69 million years.
Many people tend to walk at about 1.42 metres per second (5.1 km/h; 3.2 mph; 4.7 ft/s). [ 1 ] [ 2 ] [ 3 ] Individuals may find slower or faster speeds uncomfortable. Horses have also demonstrated normal, narrow distributions of preferred walking speed within a given gait , which suggests that the process of speed selection may follow similar ...