# math

posted by .

1.The remains of an old campﬁre are unearthed and it is found that there is only 80% as much radioactive carbon-14 in the charcoal samples from the campﬁre as there is in modern living trees. If the half-life of carbon- 14 is 5730 years, how long ago did the campﬁre burn?

• math -

Po = Poe^kt

1/2 = e^5730k

Ln(1/2) = Lne^5730k

Ln(1/2) = 5730k

K = ln(1/2)/5730

Poe^ln(1/2)/5730 *t

.80P0 = Poe^ln(1/2)/5730 *t

.8 = e^ln(1/5)/5730 t

ln(.8) = ln(.5)/5730t lne

ln(.8) = ln(.5)/ 5730 t

t = 5730ln(.8)/ln(.5)

• math -

t=1844.65 years

• math -

found in an Egyptian pyramid contains 75% of its original carbon_14 which has about 5730 years as half-life.

## Similar Questions

1. ### Calc II

Carbon-14 has a half-life of 5700 years. The charcoal from a tree killed in the volcanic eruption that formed Crater Lake in Oregon contained 59.5% of the carbon-14 found in living matter. Approximate the age of Crater Lake.
2. ### Chemistry

The half-life for radioactive decay of 14C is 5730 years (it emits β-particles with energy of 0.16 MeV). An archaeological sample contained wood that had only 72% of the 14C found in living trees. What is its age?
3. ### MATH

A track meet awards 6, 5, 4, 3, 2 and 1 points for 1st, 2nd, 3rd, 4th, 5th and 6th places, respectively. Team A’s only two runners originally earned 6 points in the ﬁrst race with both runners ﬁnishing in the top 6, …
4. ### ChemB

measurements of carbon 14 taken from linen wrappings of the book of isaiah from the dead sea scrolls indicate that the scrolls contain 79.5% of the carbon 14 expected in living tissue. how old are these scrolls if the half life of …
5. ### math

only 5% of the carbon-14 in a small wooden bowl remains , how old is the bowl?
6. ### physics

A cylindrical ﬁshing reel has a mass of 0.899 kg and a radius of 5.21 cm. A friction clutch in the reel exerts a restraining torque of 1.43 N · m if a ﬁsh pulls on the line. The ﬁsherman gets a bite, and the reel …
7. ### Chemistry

A sample of charcoal is found to have only 1/8th of Carbon-14. Half-life of Carbon-14 is 5730yrs, what is the age of the charcoal?
8. ### Science

Choose the explanation that does the following: (1) identifies the element used in carbon dating and (2) explains why the element is used. A. iodine-131; iodine is present in the thyroid glands, is radioactive, and has a very long …
9. ### chemistry

Radioactive waste is difficult to dispose of due to the long time periods needed before the radiation effectively disappears. The US protocol is to store the waste for 10 half-lives of the material after which the waste is no longer …
10. ### College Algebra

This exercise uses the radioactive decay model. A wooden artifact from an ancient tomb contains 80% of the carbon-14 that is present in living trees. How long ago was the artifact made?

More Similar Questions