Intro to Astronomy
posted by M.T.
The halflife of carbon 14, which is commonly used to date organic materials, is 5700 years. What is the minimum age of sample in which less than 1% of the organic carbon 14 is left?

drwls
If 1% is left,
(0.01) = (0.5)^N
where N is the number of halflives.
N = 6.644
minimum age = 37,900 years
There will be less than 1% left if the sample is older than that, so that is a minimum age.
There is not much about astronomy here 
Anonymous
Find the age for a rock for which you determine that 68% of the original uranium238 remains, while the other 32% has decayed into lead.
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