Posted by Peter on Friday, February 17, 2012 at 1:03am.
This may not be the math process you want. From a chemists standpoint, I would do the following.
ln(No/N) = kt. We must determine k.
So at zero time we start with 20 g. At the end of 1 day we have 20g-5% = 19 g. Plug that into the first order equation of ln(20/19) = k(1 day)
k = 0.0513
Then ln(20/10) = 0.0513(t)
Solve for t. If I didn't goof that is
13.51 days which I would round to 13.5 days.
Using the "continuous" decay formula, I got
.5 = 1(e^(-.05t) )
ln .5 - -.05t lne, but ln e = 1
t = -.05/ln .5 = .072134.. years
= 26.3 days
I looked up the half life of P-32. It is 14.28 days. I suspect 5% decay in the problem is just a close number.
Related Questions
Chemistry - The half-life of phosphorus-32 is 14.26 days. The decay constant is ...
Linear Algebra - whats the exponential decay equation for 100 atoms that decay 1...
chemistry - You have 11.20 grams of a compound. It is known that the compound ...
Chemistry - You have 11.20 grams of compound. It is known that the compound has ...
Calculus - Radius decays at a rate of that is proportional to its mass, and has...
Chemistry - How to figure out half-lives Half-live of Indium-116 is 14 seconds. ...
chemistry - Write a partial decay series for Po-214 undergoing the following ...
Math - _The_Natural_Base_e_ An accident in 1986 at the Chernobyl nuculear plant ...
physics - 1)7Be decays with a half-life of about 53 d. It is produced in the ...
chem - Write a partial decay series for Rn-220 undergoing the following ...
For Further Reading
