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.

The half-life is independent of concentration, temperature, and pressure, i.e., the t 1/2 is a characteristic constant of a radioisotope. Natural radioactive isotopes usually have a longer half-life, e.g., t 1/2 carbon-14 is 5730 years and uranium-235 is 7.0 x 10 8 years.

2023年11月3日 · The fact that isotopes have a unique half-life has proven perhaps humanity’s most powerful tool for understanding the deep history of our planet. But what is a half-life, how do we use them...

Here are the different half-life measures and what they mean. The below table presents some of the radioactive isotopes associated with a nuclear power plant with their physical and biological half-lives.

2024年8月12日 · Half-life refers to the length of time it takes for half of the atoms of a particular isotope to decay. However, half-life is a process of exponential decay, which means that after each half...

2024年8月16日 · Find the half-life of an isotope given graphical or other data. Describe how carbon-14 is used to determine the age of carbon-containing objects. During natural radioactive decay, not all atoms of an element are instantaneously changed to atoms of another element.

2022年8月13日 · The half-life of a specific radioactive isotope is constant; it is unaffected by conditions and is independent of the initial amount of that isotope. Consider the following example. Suppose we have 100.0 g of 3 H (tritium, a radioactive isotope of hydrogen). It has a half-life of 12.3 y.

2024年11月5日 · In radioactivity, half-life describes the time it takes for half of the atoms in a sample of a radioactive substance to decay. The half-life is a fixed characteristic of that substance and is independent of the amount of material present.

2025年2月1日 · Different radioactive isotopes consist of different half-lives. For example, the half-life of copper-61 is about 3.5 hours while the half-life of plutonium-240 is approximately 6537 years! A graph is a good way to find out the half-life of a substance.

2024年11月30日 · Half-life is defined as: The time it takes for the number of nuclei of a sample of radioactive isotopes to decrease by half. In other words, the time it takes for the activity of a sample to fall to half its original level. Different isotopes have different half-lives and half-lives can vary from a fraction of a second to billions of years in ...