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After 3 half lives of a radioactive substance remains A al B one half C one third D one eighth?
Wiki User
∙ 15y ago
D. One eight
Wiki User
∙ 15y ago
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What is the percentage of radioactive nuclei left after 3 half lives have passed?
12.5%
What fraction of a radioactive sample decays after three half lives?
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.
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 does the rate of chemical reaction decrease over time?
Because radioactive substances have half lives. This decreases the radioactivity in the substance.
Do radioactive isotopes need thousands of years to decay?
Half-lives of radioactive isotopes are between several nanoseconds and more than 10e22 years.
What is the percentage of radioactive nuclei left after 3 half lives have passed?
12.5%
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 fraction of a sample remains after three half lives?
An eighth remains.
What is halflife about?
Half-life is the time it takes for one half of the radioactive material to decay. It is logarithmic, so after two half-lives, one quarter remains - then one eighth - etc.
Why After three half-lives what fraction of a radioactive sample remains?
The fraction that remains is 1/8.
What percentage of a radioactive sample remains after 5 half-lives?
3.1 %
After three half-lives what fraction of a radioactive sample remains?
1/8 of the original amount remains.
What fraction of a radioactive sample decays after three half lives?
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.
How many half-lives have passed in a rock containing one eighth of the original radioactive material and seven eighths of the daughter product?
3 half-lives
Calculate how many half lives have passed in a rock containing one-eighth the original radioactive material and seven eighths of the of the daughter product?
1/8 = (1/2)3 which is in the form (1/2)n where n is the number of half lives undergone. Therefore the substance has passed three half lives
What is the problem with disposing of radioactive wastes is that they have a long what?
Radioactive substances have half-lives. This is because the isotope constantly is changing from the radioactive isotope to a daughter element. For example, eventually, when uranium's radioactivity is gone, it becomes lead. After one half life of a radioactive substance, only 50% of that substance is still radioactive. Therefore, after one half-life, a piece of uranium is 50% lead and therefore %50 less radioactive. After another half-life, it has 25% of the original radioactivity, and 75% of the original uranium has become lead. This is the problem with radioactive wastes. It takes many years just for one half lives for some substances, such as uranium. Because radioactivity is harmful, those substances have to be stored until they are no longer radioactive. So, in short, the problem with disposing of radioactive wastes is that they have long half-lives. (although this is not true with ALL substances because some have short half-lives, but, in general, radioactive substances have long half-lives.
How can half lives be shortened?
Half life of an element can't be changed.. It is a characteristic of a radioactive element which is independent of chemical and physical conditions.. Half life is that time in which half of radioactive sample( i.e., a radioactive element) decomposes. So no matter what amount you take half life of an element remains same.
