# U pb dating half life

The table below illustrates half-lives for selected elements.In addition, the final elemental product is listed after the decal process.Each radioactive isotope will have its own unique half-life that is independent of any of these factors.Figure \(\Page Index\): For cobalt-60, which has a half-life of 5.27 years, 50% remains after 5.27 years (one half-life), 25% remains after 10.54 years (two half-lives), 12.5% remains after 15.81 years (three half-lives), and so on. The half-lives of many radioactive isotopes have been determined and they have been found to range from extremely long half-lives of 10 billion years to extremely short half-lives of fractions of a second.A useful concept is half-life (symbol is \(t_\)), which is the time required for half of the starting material to change or decay.

Remember, the half-life is the time it takes for half of your sample, no matter how much you have, to remain.

After 720 hours, how much of the original \(\ce\)-225 remains? Solution To determine the number of half-lives (n), both time units must be the same.

\[720\cancel\times \dfrac= 30\, days\] \[n=3 =\dfrac\] \[\text = \dfrac (8.0 \, ug)\] After 720 hours, 1.0 ug of the material remains as \(\ce\)-225 .

Lastly, accuracy of C-14 dating has been affected by atmosphere nuclear weapons testing.

Fission bombs ignite to produce more C-14 artificially.