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What fraction of a radioactive sample decays after three half lives?
Wiki User
∙ 12y ago
If I take a radioactive sample of 400 moles of an unknown substance and let it decay to the point of three half-lives I would have 50 moles left of the sample. 1/2 of what is left will decay in the next half-life. At the end of that half-life I will have 25 moles left of the unknown substance or 4/25.
Wiki User
∙ 12y ago
Wiki User
∙ 11y agoOne eighth of the original.
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What is the percentage of radioactive nuclei left after 3 half lives have passed?
12.5%
If the isotope have short half lives is that mean that the isotope is in a stable condition?
No. Only radioactive elements have half-lives, the half-life is the time that it will take for half of the atoms in a sample of a radioactive isotope to decay into another element or isotope. This is a constant property of the isotope and does not depend on the sample size. Stable isotopes never decay.
After 6 half-lives What percentage of a radioactive sample remain?
After 6 half lives, the remaining will be (1/2)6 i.e 1/64 th of the initial amount. Hence by percentage it would be 1.5625 %
A sample contains 1200 radioactive atoms of a particular nuclide After an interval of two half-lives how many atoms have disintegrated?
After two half life it must be 1200 x 1/2 x 1/2 = 300 atoms.
What fraction of a radioactive sample remains after one half-life?
Half of the original sample of a radio isotope remains after a half-life period. After two half-life periods, one-fourth of the radio isotope remains.
Why After three half-lives what fraction of a radioactive sample remains?
The fraction that remains is 1/8.
After three half-lives what fraction of a radioactive sample will remain?
Approx 1/8 will remain.
After three half-lives what fraction of a radioactive sample remains?
1/8 of the original amount remains.
What fraction of a radioactive sample remains after three half-lives?
Not sure what you mean by "had-lives". After 3 half lives, approx 1/8 would remain.
What percentage of a radioactive sample remains after 5 half-lives?
3.1 %
What is the percentage of radioactive nuclei left after 3 half lives have passed?
12.5%
What fraction of a sample remains after three half lives?
An eighth remains.
What does the half life of a radioisotopes indicate?
The half life of a radioisotope indicates the rate of decay for a radioactive sample
Determine the amount of time it takes for three fourths of a radioactive sample of an isotope to decay?
The half-life is 4 days. That means half of it will be gone in 4 days, and that leaves half of the original sample. In another 4 days, half of the remaining half will have decayed. And that will leave only 1/4 th of the original sample. That means 3/4 ths of the original sample will have decayed. In 8 days, three fourths of a sample of a radioactive element with a half-life of 4 days will have decayed.
If the isotope have short half lives is that mean that the isotope is in a stable condition?
No. Only radioactive elements have half-lives, the half-life is the time that it will take for half of the atoms in a sample of a radioactive isotope to decay into another element or isotope. This is a constant property of the isotope and does not depend on the sample size. Stable isotopes never decay.
What fraction of a radioactive nuclei remain after p half lives?
The remainder is 2-p or 0.5p of the original amount.
How much of a 400-gram sample of K40 is left after 2 half-lives?
After the first half-life, you will have one half of the starting amount. After a second half-life period, you'll be down to one quarter. Of the part that radioactively decays, about 11% of it will decay to 40Ar, and the remainder to 40Ca. Of your total sample of ordinary potassium, only 0.012% will be 40K. The half-life of 40K is about 1.3x109 years.
