How was the half-life of uranium-238 determined?
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How was the half-life of uranium-238 determined?
The half-life is then determined from the fundamental definition of activity as the product of the radionuclide decay constant, λ, and the number of radioactive atoms present, N. A = 1014 cpm/0.315 c d-1 = 3219 dpm = λ N = (ln2/T1/2)(4.41 x 10-3 g/238.03 g/g-atomic weight)(6.022 x 1023 atoms/g-atomic weight).
How old is the rock if the half-life of uranium-238 is 4.5 billion years?
9 BY old
Since the half-life of U-238 is 4.5 Billion years, this rock must be 9 BY old.
Why does uranium-238 have such a long half-life?
Uranium-238 (238U or U-238) is the most common isotope of uranium found in nature, with a relative abundance of 99\%. Unlike uranium-235, it is non-fissile, which means it cannot sustain a chain reaction in a thermal-neutron reactor….Uranium-238.
| General | |
|---|---|
| Protons | 92 |
| Neutrons | 146 |
| Nuclide data | |
| Natural abundance | 99.2745\% |
How do you figure out how long a half-life is?
So, if a problem asks you to calculate an element’s half-life, it must provide information about the initial mass, the quantity left after radioactive decay, and the time it took that sample to reach its post-decay value. Therefore, its half-life is t1/2=98.012.7=7.72 years .
What do you know about half-life?
Half-life (symbol t1⁄2) is the time required for a quantity to reduce to half of its initial value. The term is commonly used in nuclear physics to describe how quickly unstable atoms undergo radioactive decay or how long stable atoms survive.
How long is uranium-238 half?
about 4.5 billion years
The half-life of uranium-238 is about 4.5 billion years, uranium-235 about 700 million years, and uranium-234 about 25 thousand years.
Is the half-life the same length of time for carbon 14 and uranium-238 transitions?
Explanation: Carbon 14 with a half life of 5,700 years can only be used to date fossils of approximately 50,000 years. Most fossils are thought to be much older than 50,000 years. Uranium 238 has a half life of 4.5 billion years.
How is the half-life of a radioactive isotope defined?
half-life, in radioactivity, the interval of time required for one-half of the atomic nuclei of a radioactive sample to decay (change spontaneously into other nuclear species by emitting particles and energy), or, equivalently, the time interval required for the number of disintegrations per second of a radioactive …