# Algebra 2

posted by .

half life carbon -14 is 5,730 years. If you start out 50 grams, how long will it take until it reaches 2 grams?

• Algebra 2 -

x = Xi e^-kt
x/Xi = .5 = e^-5730 k
ln .5 = -5730 k
-.69315 = -5730 k
k = 1.21*10^-4

x = Xi e^-1.21*10^-4 t
2 = 50 e^-1.21*10^-4 t
.04 = e^-1.21*10^-4 t
ln .04 = -1.21*10^-4 t
-3.22 = -1.21*10^-4 t
2.66 * 10^4
= 26,600 years

## Similar Questions

1. ### oceanography

14C has a half-life of 5,730 years. If we start with 70 grams of 14C at time zero how many grams of 14C will be left after three half-lives?
2. ### Math

An unknown radioactive substance has a half-life of 124 years. How long will it take a 67 grams sample to degrade to 18 grams?
3. ### Pre Calculus

Tritium, a radioactive isotope of hydrogen, has a half-life of 12.4 years. Of an initial sample of 69 grams, how much will remain after 75 years?
4. ### science

The half-life of carbon-14 is 5730 years. If we start with 10 grams of carbon-14, after 5730 years, we will have _____ of carbon-14 left.
5. ### science

The half-life of carbon-14 is 5730 years. If we start with 10 grams of carbon-14, after 5730 years, we will have _____ of carbon-14 left.
6. ### oceanography

14C has a half-life of 5,730 years. If we start with 70 grams of 14C at time zero how many grams of14C will be left after three half-lives?
7. ### math

Carbon-14 has a half-life of 5730 years. How long will it take 17 grams of carbon-14 to be reduced to 10 grams?
8. ### Physics

(a)-A fossilised tree was tested and contains 10 grams of Carbon-14. Given that there was 12 grams of Carbon-14 present when it died, determine the age of the fossil?
9. ### Intermediate Maths

(a)-A fossilised tree was tested and contains 10 grams of Carbon-14. Given that there was 12 grams of Carbon-14 present when it died, determine the age of the fossil?
10. ### Physics

(a)-A fossilised tree was tested and contains 10 grams of Carbon-14. Given that there was 12 grams of Carbon-14 present when it died, determine the age of the fossil?

More Similar Questions