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Re: [Phys-l] thorium-228



Ludwik!

ppb moles, atoms, molecules, etc.???


Plugging and chugging W/O much thought:


Activity = decay constant times number of nuclei
decay constant = half life / Ln(2)
37 GBq / Ci

Therefore N = 1.15 E+15 nuclei. Compare this to A = 6.022 E+ 23 nuclei per mole. I doubt very much you used Th metal. Th is most commonly? (IV), e.g ThCl(4)

bc missing something?



On 2009, Dec 25, , at 15:01, ludwik kowalski wrote:

Not trusting myself, I would like someone to confirm that the answer below is correct.

Question: Th-228 (half-life 1.913 years) is dissolved in water, at the concentration of 0.03 ppb. What is the activity of that isotope? (ignore activity of daughters).

Answer: 3.57*10^-4 Ci.

Thanks in advance,

Best wishes to all,

Ludwik
= = = = =

Ludwik's new book (AUTOBIOGRAPHY) see:

http://pages.csam.montclair.edu/~kowalski/mybook2.html


Share this link with those who might be interested. Thanks in advance.



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