Question 170399
A certian radioactive substance decays according to the formula 
A(t) = Aoe^-0.0063t where t is time in days. What is the half life 
of this substance (to the nearest day)?
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If you start with Ao then A(t) = (1/2)Ao will determine the halflife.
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(1/2)Ao = Aoe^-0.0063t
(1/2) = e^-0.0063t
Take the natural log to get:
-0.0063t = ln(0.5)
t = ln(0.5)/-0.0063
t = 110.0233620 years
0.0233620*365 days = 8.527.. days
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Ans: Halflife = 110 yrs + 8.527 days
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Cheers,
Stan H.