half-life (hăf′līf′) The average time needed for half the nuclei in a sample of a radioactive substance to undergo radioactive decay. The half-life of a substance does not equal half of its full duration of radioactivity. For example, if one starts with 100 grams of radium 229, ...
Radioactive datingis a clever use of naturally occurring radioactivity. Its most famous application iscarbon-14 dating. Carbon-14 has a half-life of 5730 years and is produced in a nuclear reaction induced when solar neutrinos strike14N in the atmosphere. Radioactive carbon has the same chemistr...
The term half-life is appropriate due to the exponential and quantum nature of radioactive decay, which makes it impossible to predict exactly when a single atom of radioactive material will disintegrate. The half-life measurement instead relates to statistics, representing the time it takes for ...
Half-life, in radioactivity, the interval of time required for one-half of the atomic nuclei of a radioactive sample to decay, or, equivalently, the time interval required for the number of disintegrations per second of a radioactive material to decrease
half-life [haf´līf″] the time required for the decay of half of a sample of particles of a radionuclide or elementary particle; see also radioactivity. Symbol t½ or T½. Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by...
full duration of radioactivity. For example, if one starts with 100 grams of radium 229, whose half-life is 4 minutes, then after 4 minutes only 50 grams of radium will be left in the sample, after 8 minutes 25 grams will be left, after 12 minutes 12.5 grams will be left, and so ...
Discover radioactive decay and the half-life equation. Learn how to use a half-life graph to write the equation for an atom's half-life and...
half-life (redirected from half-lifes)Also found in: Dictionary, Thesaurus, Medical, Financial. half-life half-life, measure of the average lifetime of a radioactive substance (see radioactivity) or an unstable subatomic particle. One half-life is the time required for one half of any ...
It is known that the radioactive substance carbon-14 has a half-life of 5,570 years. The half-lives of other radioactive substances can range from tiny fractions of a second to quadrillions of years. [ See also Dating techniques ; Geologic time ; Isotope ; Radioactivity ] Also read ...
Half-life and electromagnetic deexcitation rate measurements for 12+ and 32+ states in odd-proton nuclei around Z=82doi:10.1016/0375-9474(86)90031-XRadioactivityHalf-lives of 32+ levels in odd-mass Bi nuclei and of 12+ levels in 187,191Au have been measured using mass-separated sources ...