Saturday

March 28, 2015

March 28, 2015

Posted by **j** on Friday, July 24, 2009 at 1:11pm.

1. Find the rate of change of an initial amount of 1 gm of carbon-14 found in the scrolls, if the decay constant is given as λ = 1.21 x 10-4.

2. If the percentage of carbon-14 atoms remaining in a sample is 79%, how old is the sample?

- calculus -
**MathMate**, Saturday, July 25, 2009 at 9:00am1.

dN/dt = -λN

so the initial rate of change

= -1.21*10^4 × 1 g/year

= -0.000121 g/year

2.

N = N_{0}e^{-λt}

e-λt = N/N_{0}

taking logs on both sides

-λt = ln(N/N_{0})

t = -ln(N/N_{0})/λ (before present, year 1950)

= -ln(0.79)/(1.21*10^{4}) (BP)

= 1948 (BP)

**Answer this Question**

**Related Questions**

calculus - The rate at which an amount of a radioactive substance decays is ...

Math - D.E.Q. - The half-life of a radioactive isotope is the amount of time it ...

8th Grade Earth Science Help? - Which of the following terms refers to the time ...

Calculus - [Exponential growth & decay] The half-life of radioactive strontium-...

Calculus - The half-life of radioactive strontium-90 is approximately 31 years. ...

Algebra - The half-life of a specific radioactive compound is 20 years. The ...

Science - Can someone please please help me? I don't have a text book, i have a ...

earth science - what would be the chart to use for carbon 14 whcih has a half ...

Physics - Let us assume that the muon production happens at an altitude of about...

chemistry - Radioactive waste is difficult to dispose of due to the long time ...