The property of some materials by which individual atoms decay, emitting energy or particles often transforming into different elements in the process.

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Do supernovae produce an appreciable amount of lithium?

David Z's answer to this question got me wondering - is any appreciable amount of lithium produced as the result of a supernova explosion, either by fusion (which seems unlikely to me, but I don't ...
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1answer
30 views

Is anisotropic radioactivity really impossible?

What if the nucleus has a magnetic moment, and also the electron shell has one? I suspect, in this case, the orientation of the nucleus could be "fixed" by the electron shell. Maybe a mono-crystal of ...
6
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3k views

Effect of temperature on radioactivity?

I'm researching the effect of temperature on uranium radioactivity, however I can't find any solid empirical evidence to prove the notion that temperature does not affect radioactivity. Can anyone ...
19
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3answers
971 views

Long time deviations from exponential decay in radioactivity

Are there any examples of common substances whose decay is not exponential? We're used to thinking about radioactivity in terms of half-lives. This is a concept that makes sense only for a decay that ...
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3answers
41 views

Growth and Decay, Law or not?

The differential equation for decay that applies to radioactive decay is: $$dN/dt=-kN$$ for a positive constant k and number of particles N. My question is: is this, strictly speaking, a "Law"? I ...
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1answer
76 views

Are all radioisotopes equally dangerous? [closed]

I'm currently writing an issues investigation on the radioisotope plutonium-239. It's difficult to talk about the dangers of the radioisotope itself, since information on the internet is mixed. ...
3
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1answer
38 views

Why does a CfBe neutron source not exist?

Sources such as AmBe take advantage of Beryllium's $(\alpha,n)$ process to produce high energy neutrons. Sources such as Cf utilize spontaneous fission. Why not combine the two? Such a source would ...
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1answer
111 views

Who determined the half-life of Uranium 235 and how?

By Wiki, the half-life of Uranium 235 is as long as 703,800,000 years. This is huge. Therefore, on an human time scale, the decay is very small. This should pose difficulty for determining the half-...
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3answers
9k views

Would being underwater help survive a nuclear bomb?

If I jump in my pool, on the river near my house knowing that a nuclear bomb, or atomic or H-Bomb exploded around 10 km from my house, would I survive? The way I see it is that water will protect me ...
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2answers
105 views

How can quantum tunnelling lead to spontaneous decay?

I have never understood what measuring process (if any) is supposed to be continuously polling the quantum state of an unstable bound system subjected to decay via quantum tunnelling. The reason I ...
9
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4answers
2k views

What is happening over the 15 minutes it takes a neutron to decay?

I've read that free neutrons decay into a proton, electron and neutrino with an average lifespan of about 15 minutes. Is there anything physically different about a neutron that has existed for 14 ...
2
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4answers
1k views

Is it possible to produce gamma radiaton using radio emitter?

As in the title, I'm wondering is it possible. I think it is possible, because we have powerful enough radiotechniques and gamma radiation are just EM waves, not particles. However I think is useless,...
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3answers
304 views

Can we find the exponential radioactive decay formula from first principles?

Can we find the exponential radioactive decay formula from first principles? It's always presented as an empirical result, rather than one you can get from first principles. I've looked around on the ...
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3answers
4k views

Artificial planetary magnetic field

I wonder how difficult it is to create an artificial planetary magnetic field with generators? What power they would need? The question is inspired by thinking about possible colonization of Jupiter'...
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2answers
8k views

Is radioactive decay spontaneous or random?

When the count rate of a radioactive isotope is measured, the readings fluctuate. Do the fluctuations demonstrate the random nature of the decay or the spontaneous nature? (This question was asked in ...
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1answer
41 views

Cause of radioactivity

If Uranium-238 is hit by a neutron, it splits into different parts. My question is (a) Why throwing a neutron will destroy the equilibrium? Rather, should it not help maintain it? (As neutron is ...
3
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1answer
84 views

Measuring very long half lives accurately

There are already some questions about long half life times for radioactive elements, explaining how to calculate the half life time. Now I am wondering: When you have some radioactive material and ...
0
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1answer
19 views

Why is beta-minus decay considered isobaric?

Page 20 of Physics in Nuclear Medicine says that beta-minus decay is isobaric (eg the A/Z ratio remains the same). The reason it gives is that "mass number A does not change." However, in beta-minus ...
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1answer
47 views
5
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315 views

Beta decay: is it OK that the products are not electrically neutral?

I'm just learning about radioactivity, and there's one thing I'm unclear about. Take $\beta -$ decay, for example. Since a neutron splits into a proton and an electron (and an anti neutrino), but ...
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2answers
61 views

Radioactive decay-Why does it depend on numbers left

As textbooks describe the rate law for radioactive decay as a first order reaction dN/dt=kN,why is it so(mine does not give the reason)? How is the radioactive decay of one atom depeendent on the ...
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0answers
18 views

Protonic emissions

In a beta emission a neutron decays,into a proton and an electron, and an electron randomly gets ejected from the nucleus due to the phenomenon of barrier tunnelling(correct me if am wrong).But why is ...
43
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3answers
7k views

Can radioactivity be slowed through time dilation?

Can radioactivity be slowed using the effect of time dilation? If you put cesium, tritium or uranium in a cyclotron at relativisitic speeds, do their half lives become longer in our frame? Could ...
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2answers
65 views

Question about calculating age of a uranium and lead containing object, based on the ratio of uranium-to-lead

I realize this is probably going to sound so stupid, but... here goes: Radioactive decay: We know that we can calculate the age of a uranium containing object by the uranium-to-lead ratio, due to ...
0
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1answer
14 views

Why does natural counting with a gamma spectrometer differ from Neutron activation analysis?

As stated in the title, why are the data from natural counting using s gamma spectrometer different than the data from neutron activation analysis using the same samples?
0
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2answers
41 views

Can electron capture occur with an external electron?

Can electron capture proceed with an electron not bound to the nucleus which decays (that is one that is bound to a neighboring atom, bound in a collective state like a conduction band, or free)?
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1answer
97 views

Radioactive decay of Uranium 238

Problem We have a cubic room of side $10$ m, into which no fresh air has been allowed to flow for a week. We register a specific activity of radon ($Rn-222$) of $50$ Bqm$^{-3}$. Knowing that $Rn-222$ ...
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33 views

Sustained nuclear criticality in liquid vortex

In 1958, chemical operator Cecil Kelley was killed by a nuclear excursion in a mixing tank. A tank intended to reprocess trace amounts of dissolved plutonium-239 accidentally had dramatically more ...
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2answers
98 views

Safety of Polonium Isotope source

I saw a YouTube video by a guy demonstrating Geiger Counter use and one of his radioactive test sources was a disk with Polonium. He casually mentioned that this was the poison used to kill that ...
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4answers
11k views

Why is technetium unstable?

Is there a simple account of why technetium is unstable? From the Isotopes section of Wikipedia's article on Technetium: Technetium, with atomic number (denoted Z) 43, is the lowest-numbered ...
3
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0answers
27 views

Detection of radioactive iodine at trash dumps [closed]

I have a cat that is getting radioactive iodine therapy and I am told I must flush the litter for 2 weeks because if I throw it away normally the dump will detect the radiation and fine me. This ...
2
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1answer
65 views

XP Decay mode of radioactive nucleus

The decay mode of Carbon-8 is listed as 'XP' in this table. None of the references I looked at listed XP as a decay mode. What is it?
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1answer
98 views

Long distance radiation detection, David Hahn and the clock

The strange character David Hahn, obsessed with creating a nuclear reactor since a young age, was reportedly wandering around his neighborhood with a Geiger counter and by this means he located a ...
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0answers
26 views

Why is nuclear waste, waste? [duplicate]

My colleagues and I are chatting and none of us know why nuclear waste is waste. That is to say, if something is still radioactive, why can't that radiation be used? Can't the energy from, at least ...
0
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3answers
66 views

Are Geiger counters isotope-specific?

I was talking with an employee at a company that does I-131 therapy for hyperthyroidism and they said that the Geiger counters they use are "tuned" for I-131, implying that regular Geiger counters are ...
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2answers
148 views

Calculate the probability that a radioactive nucleus will have decayed after the passage of three half-lives

This is a problem given in my Physics Textbook and I've been trying to solve it for the past hour. It's not something exceptionally challenging, but more conceptual in nature. Not much, connections ...
3
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2answers
59 views

Beta decay of radiocarbon

I read some weird equation on wikipedia about the beta decay of radiocarbon: ${^{14}_{6}C} \rightarrow {^{14}_{7}N} + e^{-} + \overline{\nu_{e}}$ The problem with this equation that it does not ...
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2answers
43 views

What happens to covalent bonds after the nuclear transmutation of an atom in a molecule?

What happens when we have a decaying atom in a molecule, which has covalent bonds with other atoms? I assume some of the bonds will cease to exists, but I did not manage to find any rule about which ...
6
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2answers
2k views

What happens to chemical compunds that include radioactive nuclei, when those decay?

Say you have a chemical compound made up of one or more radioactive nuclei. If the nucleus decays, does the compound? Possible outcomes I can think of: the compounds continues to exist if a ...
7
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2answers
701 views

Can a half life be given in electron volts?

I'm using this link to search for particular energies in which gammas may be emitted (for nuclide identification on a gamma spectrum). If on the above link you go down to the "γ condition #1" line, ...
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1answer
569 views

When will an atom emit alpha particle, beta particle, or gamma rays?

How can we predict which particle the radioactive element will emit?
3
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3answers
369 views

Can one see radioactive substances with an X-ray detector?

I was wondering the other day an X-ray detector (like the ones used at airports) can detect gamma-rays lets say from a sample of uranium. I know its all electro-magnetic waves but I'm really unsure ...
3
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2answers
274 views

Does hotter radioactive substance have longer half life?

Sorry to have a newbie question! But I want to ask, if it is possible to change the half life of radioactive substance by heating it, my hypothesis is: When substance becomes hotter, the kinetic ...
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2answers
379 views

What is the theoretical wattage output of a Tokamak fusion reactor?

By that I mean the complete radiative wattage of any type of energetic radioactivity or electromagnetic wave or even particle if that's what they output. My purpose is to compare this to the suns ...
4
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5answers
15k views

Iodine-131 half-life and reality

Iodine is a chemical element with symbol I and atomic number 53. There is currently a lot of discussions regarding radioactivity in Japan, and iodine-131. Iodine-131 has a half-life of 9 days. Does ...
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1answer
39 views

Can alpha, beta or gamma radiations emitted by a radioactive substance be controlled? [duplicate]

Just saw this question in a school class 10 exam. Google search did not yield useful results. Can anyone please explain the answer here?
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1answer
56 views

Predict decay chain of a radioactive element

I know there are tables of decay chain of radioactive elements. Is there a way to predict the whole chain from the first radioactive element?
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0answers
32 views

Confusion about radioactivity

The following question is from General Problems on Physics by I.E Irodov 6.220. Find the decay constant and the mean lifetime of $^{55}\operatorname{Co}$ radionuclide if its activity is known to ...
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0answers
32 views

Peak in continous energy spectrum

I was reading online about particle decay. For the decay of Strontium-90 to Yttrium-90, a beta particle is emitted. The energy distribution of beta particle is continuous. If I know that the maximum ...
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3answers
29 views

Measuring Activity

The formula for Activity of a radioactive substance is $ \frac{dN}{dt}=A=λN $. If we have an initial number $N(0)$ of some Radionuclide, which has a halflife of, say, 12 hours, is there any ...