96.875%

11.25 mg

Decay Rate The half-life (t1/2) is the time taken for the activity of a given amount of a radioactive substance to decay to half of its initial value. The mean lifetime (τ, “tau”) is the average lifetime of a radioactive particle before decay. The decay constant (λ, “lambda”) is the inverse of the mean lifetime.

Half-life, in radioactivity, the interval of time required for one-half of the atomic nuclei of a radioactive sample to decay (change spontaneously into other nuclear species by emitting particles and energy), or, equivalently, the time interval required for the number of disintegrations per second of a radioactive …

Radioactive decay reduces the number of radioactive nuclei over time. In one half-life t1/2, the number decreases to half of its original value.

The average life or the mean life of a radioactive substance is given by the ratio of the total lifetime of all the individual parent atoms to the total number of such atoms present in the sample.

Average life or mean life of radioactive nucleus is defined as the ratio of total lifetime of radioactive atoms to the total number of atoms in the sample. This is the relation between half-life and average life of a radioactive nucleus. Half-life of isotope A: T1/2 A = 60 years.

Radioactive isotopes are effective tracers because their radioactivity is easy to detect. Tracers can also be used to follow the steps of a complex chemical reaction. After incorporating radioactive atoms into reactant molecules, scientists can track where the atoms go by following their radioactivity.