# Half-life functions

by drag
Tags: functions, halflife
 Sci Advisor P: 1,341 Greetings ! I'd like to ask a few questions about half-life (not the PC game ) functions: 1. Are they of the same shape for all nuclear particle decay reactions currently known and observed ? 2. What is the function mathematicly (and it's relevant shape of course) ? 3. What are the physical parameters if they are known (I guess not though) ? 4. Can the shape of the function help find a solution to the cause of the nuclear decay (if there is such a thing at all) ? Thanks ! Live long and prosper.
Emeritus
PF Gold
P: 5,532
 Originally posted by drag 1. Are they of the same shape for all nuclear particle decay reactions currently known and observed ?
Do you mean N=N0e-kt?

That is valid only for large samples, as it treats the number of radioactive species as continuous. But yes, that can be used to model large samples of any radioisotope.

 2. What is the function mathematicly (and it's relevant shape of course) ?
See above: Decaying exponential.

 3. What are the physical parameters if they are known (I guess not though) ?
You need to know the initial amount of radioactive species (N0). You can find the half life by measuring the amount of radioactive species at some later time.

 4. Can the shape of the function help find a solution to the cause of the nuclear decay (if there is such a thing at all) ?
No, it cannot. For that you have to look at the gauge theories describing the appropriate reaction. For instance, &alpha;-decay is a strong interaction, and &beta;-decay is a weak interaction.

 Thanks !
No, thank you for getting me out of the philosophy forum. I needed some air!
 P: n/a Is it understood why an atom will decay when it does, or does it just still seem spontaneous even after someone understands quantum mechanics, standard model, etc.
 Emeritus Sci Advisor PF Gold P: 5,532 Half-life functions It is indeed impossible to predict when any single nucleus will decay. All we can do is predict averages over large samples.

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