SOLUTION: This is a problem for exponential decay. I am just not understanding it. A radioactive substance has a half-life of 2 years. There is 36 g to begin with. Write and equation for

Algebra.Com
Question 146096: This is a problem for exponential decay. I am just not understanding it.
A radioactive substance has a half-life of 2 years. There is 36 g to begin with. Write and equation for y=mass left after x=half-years.
Then solve for 100 years. (how much of the 36 g will be left?)

Answer by stanbon(75887)   (Show Source): You can put this solution on YOUR website!
A radioactive substance has a half-life of 2 years.
There is 36 g to begin with.
Write and equation for y=mass left after x=half-years.
Then solve for 100 years. (how much of the 36 g will be left?)
---------------
A(t) = Ao(1/2)^(t/2)
Comment: That t/2 exponent means you should multiply by 1/2 every 2-years.
-----------------
A(100) = 36(1/2)^(100/2)
A(100) = 36(1/2)^50
A(100) = 36*0.00000000000000088817842
A(100) = 0.0000000000000319744...grams
Or
A(100) = 3.197 x 10^-14 grams
==============
============================
Cheers,
Stan H

RELATED QUESTIONS

8. Radioactive materials like uranium follow the law of uninhibited decay, which is an... (answered by josgarithmetic)
hi i got this question based on exponential methods i have tried but sadly not succeeding (answered by scott8148)
The mass of a radioactive substance follows a continuous exponential decay model, with a... (answered by ankor@dixie-net.com)
The half- life of a radioactive substance is one hundred ninety-four days. How many days... (answered by Edwin McCravy)
The half- life of a radioactive substance is one hundred ninety-four days. How many days... (answered by ankor@dixie-net.com)
The half-life of a radioactive substance is 33.3 years. a. Find the exponential decay... (answered by josgarithmetic)
A radioactive isotope has a decay rate of 2% per year. Calculate the half-life for this... (answered by Boreal)
A radioactive isotope has a decay rate of 2% per year. Calculate the half life for this... (answered by robertb)
The half-life of a radioactive substance is the time it takes for half of the substance... (answered by ankor@dixie-net.com)