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Radium-226 has a half-life of 1620 years. for a 150 gram sample, how many grams will remain after 200 years?

1 Answer

6 votes
ah, yes

if you start with P amount of something and the half life is h units (in years) and the time elapsed is t (in years) then the amount left is A

the equation is

A=P((1)/(2))^(t)/(h)


so
given
h=1620
P=150
t=200
so

A=150((1)/(2))^(200)/(1620)

A=150((1)/(2))^(10)/(81)
use your calculator
A≈137.69781917515g
about 138grams left
User Pavel Repin
by
8.5k points
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