What is the half-life of the Rubidium-87 / Strontium-87 decay chain?
Asked by
erikaVT (
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October 21st, 2009
I can’t understand this half-life thing. Shouldn’t there be more information or can I just figure it out as is?
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4 Answers
@jackm I saw that already, but I wasn’t sure if it was accurate. Could you explain it?
It is the decay of Rubidium-87 to Strontium-87. Half of the mass of rubidium will decay into strontium every 50 billion years.
“Rubidium-strontium dating is based on the beta decay of rubidium-87 to strontium-87, with a half-life of 50 billion years. This scheme is used to date old igneous and metamorphic rocks, and has also been used to date lunar samples. Blocking temperatures are so high that they are not a concern. Rubidium-strontium dating is not as precise as the uranium-lead method, with errors of 30 to 50 million years for a 3-billion-year-old sample.”
from here
All nuclei have some probability of transforming into another nucleus by ejecting energy in the form of either a photon or a particle like the beta particle(an electron) or the alpha particle (the helium nucleus) ..... and others..
Most of the things you see around you made of atoms with nuclei which are very stable… i.e. they will ‘decay’ into some other atom with very very very low probability…..
We say that the half-life of an atom is = 1/ (this probability of decay per unit of time) , .. which will be = to a very very large number number of years or thousands of years if the decay probability is very small….........
Highly Radioactive nuclei have a high probability of nuclear decay processes and hence the half life is a much smaller number….. could be microseconds or a few hours or a few years…
… we say that the #nuclei undecayed at time t = initial#nuclei * e^(- p * t) where p is the probabilty of decay per unit time and t is the elapsed time…...
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