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A pure radioactive substance has a half-life of 3 hours. How long would it take a mass of 12g of that substance to decay to 3g?
Wiki User
∙ 13y ago
Twice the half-life.
Wiki User
∙ 13y ago
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What is the correct order of nuclear decay mode for the changes from U-238 to U-234?
U-238 --> alpha + gamma + Th-234, halflife 4.51E9 yearsTh-234 --> beta- + gamma + Pa-234, halflife 24.10 daysPa-234 --> beta- + gamma + U-234, halflife 6.66 hours
What is the half life of a radioactive substance if 2.4G decays to 1.80G in 66 hours?
The half-life of a radioactive substance that decays from 2.4g to 1.8g in 66 hours is 159 hours. AT = A0 2(-T/H) 1.8 = (2.4) 2(-66/H) 0.75 = 2(-66/H) log2(0.75) = log2(2(-66/H)) -0.415 = -66/H H = 159
How many half-lives does it take for a radioactive substance to decay to 12.5 percent of its original amount?
Without posting the actual formula and working it through, let's "step through" this and figure it out. Here are the steps to finding the length of time for the amount of radionuclide to decay to about 5% its original quantity: For the 1st half-life, 50% is left. Then 25%, then 12.5%, then 6.25%, then 3.125%. That's 5 half-lives, and after a bit over 4 half-lives, you'll be down to the 5% figure. The 4 half-lives is 4 x 12 or 48 hours. So in a bit over 2 days, you're down to 5% of the original amount of this substance left. There might (and probably will) be some removal of the material through normal body processes over this time. The translation is that the rate at which the substance leaves your body is going to vary. Going through the actual formula doesn't make sense from the point of view of the biology. You ability to "get rid" of the substance will depend on what it is that you're been given and how quickly you can excrete it physiologically. That's in addition to radioactive decay. This substance, whatever it is, leaves you in those two ways. One is radioactive decay, and you will get a bit of radiation from that. The other is that your body dumps it before it decays. The ball park figure of two days stands as probably a "best answer" here. That's because even an "exact" calculation through mathematics ignores the physiological processes that will also help remove this material.
How long does it take for 75 of an original 100 silver atoms to decay?
The decay rate of atoms is typically quantified by a half-life, which is the time it takes for half of the original atoms to decay. If we assume a constant decay rate, we can estimate that it takes approximately 3 half-lives for 75 of the original 100 silver atoms to decay. If the half-life of the silver isotope is 1 hour, then it would take approximately 3 hours for 75 of the atoms to decay.
Do cadmium conduct electricity?
Yes. Cadmium is radioactive, with over 50% made up of radioactive isotopes, though the half lives so very long that they can be treated as stable for most purposes.Naturally occurring cadmium is composed of 8 isotopes. For two of them, natural radioactivity was observed, and three others are predicted to be radioactive but their decay is not observed, due to extremely long half-life times. The two natural radioactive isotopes are 113Cd (beta decay, half-life is 7.7 × 1015 years) and 116Cd (two-neutrino double beta decay, half-life is 2.9 × 1019 years). The other three are 106Cd, 108Cd (double electron capture), and 114Cd (double beta decay); only lower limits on their half-life times have been set. At least three isotopes - 110Cd, 111Cd, and 112Cd - are stable. Among the isotopes absent in natural cadmium, the most long-lived are 109Cd with a half-life of 462.6 days, and 115Cd with a half-life of 53.46 hours. All of the remaining radioactive isotopes have half-lives that are less than 2.5 hours, and the majority of these have half-lives that are less than 5 minutes. This element also has 8 known meta states, with the most stable being 113mCd (t½ 14.1 years), 115mCd (t½ 44.6 days), and 117mCd (t½ 3.36 hours).No, Cadmium is not radioactive, though it is toxic.There are, however, several radioactive isotopes of cadmium.
What is a half-life of radioactive substance if it takes 6 hours for 50 percent of it to decay?
6 hours. you have a hot one there!
If the half-life of a radioactive substance is 10 hours how long will it take for 50 percent of it to decay?
The half-life of a radioactive isotope is defined as the time taken for the isotope to decay to half of its initial mass. So to decay to 50 percent of its initial mass will take one half-life of the isotope. One half-life of the isotope is 10 hours so the time taken to decay is also 10 hours.
What are the nuclear changes during decay of copper 67?
Copper-67 undergoes beta decay with a halflife of 59 hours, becoming stable Zinc-67.
If the half life of a radioactive substance is 10 hours how long will it take for 75 percent of it to decay multiple choice question is it 15 hours 10 hours 5 hours or 20 hours?
Its 5 hours. 50% of the substance is decayed at 10 hours (that is what half life means. It's full life is 20 hours). Multiple 75% times 20 hours to find that 75% is 15 hours. Subtracrt 15 hours from 20 hours to get the answer of 5 hours for the decay of 75% of the substance.
What is the correct order of nuclear decay mode for the changes from U-238 to U-234?
U-238 --> alpha + gamma + Th-234, halflife 4.51E9 yearsTh-234 --> beta- + gamma + Pa-234, halflife 24.10 daysPa-234 --> beta- + gamma + U-234, halflife 6.66 hours
What is a radioactive element's half-life?
The time it takes for a half of the element to decay. In Example: Technetium-99 has a half life of 6 hours. If you begin with a sample of 100g, then after 6 hours you will have 50 grams, at 12 hours you will have 25 grams and so on; however it will NEVER reach 0 (it will remain in exponentially small ammounts because of the asymptote in the graph). This specific exponential decay is shown by the equation y=100(0.5)((1/6)x)
How much of a radioactive substance remains after 5 hours if it's half-life is 5 hours?
6.25
What is the half life of a radioactive substance if it takes 6 hours for 50 percent of it to decay?
That is the half-life - the 6 hours in this case.That is the half-life - the 6 hours in this case.That is the half-life - the 6 hours in this case.That is the half-life - the 6 hours in this case.
Determine the amount of time it takes for three fourths of a radioactive sample of an isotope of bromine to decay the half-life of the isotope is 16.5 hours?
About 33 hours
How much of radioactive substance remains after 15 hours if it's half life is 5 hours?
The half-life of a radioactive substance is the time that it takes for half of the atoms to decay. With a half-life of 10 days, half has decayed in this time. After 20 days, a further 10 days/another half life, a further half of the remainder has decayed, so 1/4 of the original material remains, 1/4 of 15g is 3.75 grams. This is the amount of original radioactive substance remaining, but it’s daughter isotope ( what the decay has produced ) is also present, so the original sample mass is effectively constant, especially in a sealed container. Even in an unsealed container, and assuming alpha ( helium nucleii) emission, a drop in mass per radioactive atom of 4 Atomic Mass units, compared with the original atom of, say 200 amu is only 2% mass decrease, less for heavier decaying nucleii.
How long does it takes a radioactive material to decay?
Nuclear explosions produce both immediate and delayed destructive effects. Immediate effects (blast, thermal radiation, prompt ionizing radiation) are produced and cause significant destruction within seconds or minutes of a nuclear detonation. The delayed effects (radioactive fallout and other possible environmental effects) inflict damage over an extended period ranging from hours to centuries, and can cause adverse effects in locations very distant from the site of the detonation. Further reading: http://nuclearweaponarchive.org/Nwfaq/Nfaq5.html http://en.wikipedia.org/wiki/Nuclear_fallout
How much of a radioactive substance remains after 10 hours if its half life is 5 hours?
Since half of the atoms of the original substance will have decayed after 5 hours, half of what is left will have decayed after the next five hours. The answer is 0.25 or one fourth of the original atoms will remain.
