The property of some materials by which individual atoms decay, emitting energy or particles often transforming into different elements in the process.
Questions tagged [radioactivity]
690 questions
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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 internet, but can't really find any information…
Dargscisyhp
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Since radioactive material decays how is it possible that there is any left after 4.5 billion years?
I was not able to find an answer for this question...
Some radioactive elements have half-life measured in thousands of years and some others even in millions, but over 4.5 billion years all the radioactive material that was part of the initial…
Dean Kuga
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Why do they consider radioactive matter with long half lives more dangerous than matter with a short half life?
The title says it all.
For example why is plutonium considered more dangerous than radioactive iodine?
Aheho
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Mars Curiosity Power System
Curiosity's power source comes from a radioisotope thermoelectric generator (RTG) rather than from solar panels like the two Mars Rovers. 2,000 watts of thermal power from alpha particle emission in 4.8 kg of Pu-238 (half-life 87.8 years) yields…
Michael Luciuk
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Besides transmutation, is there any way to "speed up" the decay rate of radioactive material?
I'm well aware of transmutation as a way to effectively make radioactive material decay faster, however that isn't really what I mean.
Doing a quick Google search I found references to several theoretical treatises on the subject, and a few…
krfkeith
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Radioactive decay, why such unintuitive formula?
When talking of exponential decay, as with radioactive decay, the formula used (e.g. Wikipedia and my textbook) is:
$$
N(t) = N_0e^{-\lambda t}
$$
This formula, with the decay constant $\lambda$ makes little intuitive sense. It is the ratio between…
Lucy Brennan
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can radiocarbon dating be used on living things?
I have been going through a wiki article about worlds oldest living creature. As a matter of fact its a plant, a shrub to be precise.
Wiki says that the plant age was determined by carbon dating. But what i know is that carbon dating can only be…
Vineet Menon
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from where does the beta(negative) particle get velocity from?
a neutron decays into a electron a proton and an antineutrino,the proton stays in the nucleus,why does the electron come out though it is attracted by the positively charged nucleus,from where does it gain energy to come out of the nucleus?
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Can an ensemble of meta-stable systems be prepared so their survival probability drops approx. linearly right after preparation?
In this answer dealing with details of decay theory (incl. references) it is shown that
[Given] a system initialized at $t = 0$ in the state [...] $| \varphi \rangle$ and left to evolve under a time-independent hamiltonian $H$ [... its]…
user12262
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How does the intensity of radioactive decay vary with distance?
I have a Sr-90 source which undergoes beta-decay. I measure the number of counts (n) detected by the detector as I increase the distance between source and detector. I then plot a graph of d vs (n/Δt)d^2. The graph i get is shown below.
How do I…
gemini
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If you could magically tweak the strength of nuclear force, would some radioisotopes decay faster and others slower?
As far as I understand, there are forces in opposition within a nucleus: the protons are pushed apart by their positive charge, but held together (along with neutrons) by the strong force. For a nuclide to be stable, the forces must be balanced.
In…
user3764
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Why does cluster decay almost always emit an even number of both protons and neutrons?
Looking on Wikipedia's cluster decay article, I see that almost all clusters emitted from a nucleus have an even number of both protons and neutrons (not necessarily the same number of each). The only exceptions listed are:
23F from 231Pa
25Ne from…
CJ Dennis
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Radioactive decay : question
yo for this question, I'm unsure how to approach. We cannot just say that in 1200 years, x has 3 half lives and its daughter y has 4 half lives, therefore x is double y. This approach assumes that the initial amount of x and y is the same.
How…
mar01
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Alpha Beta Gamma Biological Impact
Assume that alpha & beta particles and gamma photons each reach skin at the same energy. It's known that they penetrate most deeply in order by gamma, beta and alpha. How would they compare in terms of total biological impact? In other words, which…
Michael Luciuk
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Using photographic film to measure radioactivity
I'm asking a similar question on the Photography SE, but here I'm more curious about a measurement setup.
In short, some lens manufacturers used thorium in some of the lens elements to increase the refractive index (similar to lead crystal glass). I…
Andréas Sundström
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