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852. Problem 54.69 (RHK) A rock, recovered from far underground, is found to
contain
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of
,
of
, and
1.60 mg of
. We
have to calculate the amount of
it is
likely to contain. The needed half-lives are as follows:
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Solution: Click For PDF Version We assume that the amount of
and
We use the radioactive decay law
in the following for calculating the age of the rock and the number of
nuclides of
The disintegration constant of
The disintegration constant of
The nuclides of
Therefore, the age of the rock can be found from the relation
The age of the rock is
Let the number of nuclides of
We use again the fact that the sum of nuclides of
We find that the amount of
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,
.
.
.