SOLUTION: The level of thorium in a sample decreases by a factor of one-half every 4.2 million years. A meteorite is discovered to have only 7.6% of it's original thorium remaining. How old
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Question 165660: The level of thorium in a sample decreases by a factor of one-half every 4.2 million years. A meteorite is discovered to have only 7.6% of it's original thorium remaining. How old is the meteorite?
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
The level of thorium in a sample decreases by a factor of one-half every 4.2 million years. A meteorite is discovered to have only 7.6% of it's original thorium remaining. How old is the meteorite?
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A(t) = Ao(1/2)^(t/4.2 million)
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0.076Ao = Ao(1/2)^(t/4.2 million)
(1/2)^(t/4.2 million) = 0.076
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Take the log of both sides to get:
(t/4.2 million)*(log(1/2)) = log 0.076
t/4.2 million = [log(0.076)]/[log(1/2)] = 3.717856...
t = 3.717856...* 4.2 million
t = 15.615 million years
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Cheers,
Stan H.
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