If an isotope has a half life of 50 million years, and 1/8 of it is left, the age of the rock from which it was taken is:
A. 150 million years
B. 800 million years
C. 300 million years
D. 400 million years
Seriously, I appreciate any real help! Thank you SSSOO much in advance!
2007-12-05 13:32:29 · 4 answers · asked by Anonymous in Science & Mathematics ➔ Earth Sciences & Geology
Ok, so after 1 half-life, 1/2 of the stuff will be left. Another half-life, and 1/2 of that 1/2 will be left, in other words, 1/4 of the original will be left. One more half life, and 1/2 of that 1/4 will be left - that leaves us with 1/8 of the original.
So you've been through 3 half-lives. I'll leave it up to you to multiply 50 million by 3.
2007-12-05 13:36:15 · answer #1 · answered by kris 6 · 1⤊ 0⤋
It's A!
1/2 the first half, 1/2 of the 1/2 is 1/4 and half of that is 1/8. so three periods of 50 mil years, thats 50 mil times three... 150 mil.
2007-12-05 13:38:28 · answer #2 · answered by Slevin 2 · 1⤊ 0⤋
Sounds like it ought to be A...1/2 is left after 50 m years, 1/4 is left after 100 m, and 1/8 after 150 m. makes sense to me anyway
2007-12-05 13:36:16 · answer #3 · answered by jxt299 7 · 1⤊ 0⤋
you have replied your self, the 0.5-existence is the time it takes for 0.5 of the isotope to decay into the daughter product, 4 hundred tens of millions years 50% of the isotope may be the daughter isotope, then after yet another 4 hundred million years 0.5 of the parent isotope will decay to the daughter - 800 million years seventy 5% of the isotope could have decayed to the daughter isotope. Make sense? desire this permits.
2016-11-13 19:38:33 · answer #4 · answered by Anonymous · 0⤊ 0⤋