700 million years
The half-life of uranium-235 is approximately 703.8 million years, while the half-life of uranium-238 is approximately 4.5 billion years.
If you think to uranium 235 the half life is 703 800 000 years.
Radioactivity can persist on uranium for billions of years, as uranium has a very long half-life. The most common isotope of uranium, uranium-238, has a half-life of about 4.5 billion years. Uranium-235, another isotope, has a shorter half-life of about 700 million years.
After one half-life, half of the original amount of Uranium-235 would remain. After four half-lives, only ( \frac{1}{2^4} ) or ( \frac{1}{16} ) of the original amount would be left. Therefore, if you started with 100 grams of Uranium-235, 6.25 grams would remain after four half-lives.
The half-life is 700 million years !
The half-life of uranium-235 is approximately 703.8 million years. This means that it takes that amount of time for half of a sample of uranium-235 to undergo radioactive decay.
The half-life of uranium-235 is approximately 703.8 million years, while the half-life of uranium-238 is approximately 4.5 billion years.
The half-life of Uranium 235 refers to the time taken for half of a sample of Uranium 235 atoms to undergo radioactive decay. It is a measure of the stability of the isotope, with Uranium 235 having a half-life of about 700 million years. This property is important in dating geological samples and in nuclear energy applications.
If you think to uranium 235 the half life is 703 800 000 years.
Radioactivity can persist on uranium for billions of years, as uranium has a very long half-life. The most common isotope of uranium, uranium-238, has a half-life of about 4.5 billion years. Uranium-235, another isotope, has a shorter half-life of about 700 million years.
The half life of Uranium 235
700 million (more exactly 703,8.106) years
One Half-Life :-)
The half-life is 700 million years !
Uranium 234, 235 an 238 are all natural isotopes of uranium.Uranium 235- neutrons: 143- atomic mass: 235,043 929 918 ± 0,000 001 957- half life: 7,038.108 years- concentration in natural uranium: 0,7204 %- 235U is a fissile isotope
(4,470 ± 0,020).109 years by alpha decay and (8,20 ± 0,10).1015 years by spontaneous fission.
If a radioactive isotope has a half-life of 4 years, than 0.125 (0.53) of the isotope will remain after 12 years, or 3 half-lives.The question asked about Uranium. There is no isotope of Uranium with a half-life of 4 years. The closest is 232U92, which has a half-life of 68.9 years.Reference: http://www.nndc.bnl.gov/chart/