A sample of a meteorite has been analyzed, and the result shows that out of every 1000 nuclei of potassium-40 originally in the meteorite, only 100 have not decayed. How old is the meteorite?
_________years. can someone help me this problem again. I am still having difficulty finding out to figure this one out.
2007-11-15 11:37:33 · 3 answers · asked by sweetnovember4 2 in Science & Mathematics ➔ Astronomy & Space
I do know that the half life of potassium 40 is 1.277 billion years
2007-11-15 11:38:58 · update #1
How did the 3.4 come about?
2007-11-15 12:58:12 · update #2
3 half lives give decay to 125.
another half decays to 62.5
To decay to 100: 25 nuclei of the next 62.5 in this half life ... 25/62.5=.4 half lives ... 3 + .4 = 3.4 half lives
3.4 half lives x 1.277B= 4.3418 Bil. years
2007-11-15 13:57:10 · answer #1 · answered by 55MEG 2 · 0⤊ 1⤋
OK, it's basically just 3.4 half lives of potassium 40, or 4.3418 billion years (after 1 half life you have 500 nuclei, after 2 half lives you have 250 nuclei, and so on). Age of the Solar System is reckoned to be 4.56 or thereabouts, so that age could be possible.
2007-11-15 12:31:53 · answer #2 · answered by Bruce C 1 · 0⤊ 0⤋
Age = halflife x ln(remaining proportion)/ln(.5) (actually, you can use the base 10 log instead; it's the same either way).
2007-11-15 12:43:20 · answer #3 · answered by injanier 7 · 0⤊ 0⤋