How to find the age of boat (carbon dating)? please

  • Thread starter Tangeton
  • Start date
  • #1
62
0

Homework Statement


The carbon in living matter contains fixed proportion of the radioactive isotope carbon-14. The carbon-14 in 1.00g of living matter has an activity of 0.250Bq. The half life of carbon-14 is 5730 years.
(a) Calculate (i) The decay constant in s-1 (ii) the number of carbon-14 atoms required to produce an activity of 0.250Bq.
(b) When a plant dies the proportion of carbon-14 decreases due to radioactive decay. A 1.00g sample of carbon from an ancient boat has an activity of 0.0625Bq. Determine the age of the boat.

Homework Equations


A = yN
A = A0e-yt
A0 = yN0
A = A0e-yt

The Attempt at a Solution


I've worked out (a) (i) to be 2.48x10-12 and (ii) N = 1.01x1011

I don't know how to work out (iii) because I don't know how to work out N0 or A0. I found using A = yN --> N = A/y = 2.52x1010

How to find either A0 or N0 so that I can use A = A0e-yt or N = N = N0e-yt?
 

Answers and Replies

  • #2
Simon Bridge
Science Advisor
Homework Helper
17,857
1,655
You do it using proportions.

i.e.
What fraction of the sample was C14 when it was new?
What fraction is it now?
 

Related Threads on How to find the age of boat (carbon dating)? please

  • Last Post
Replies
2
Views
2K
  • Last Post
Replies
4
Views
2K
  • Last Post
Replies
9
Views
9K
  • Last Post
Replies
1
Views
4K
  • Last Post
Replies
1
Views
10K
  • Last Post
Replies
17
Views
369
  • Last Post
Replies
8
Views
1K
  • Last Post
Replies
2
Views
2K
Replies
7
Views
2K
  • Last Post
Replies
20
Views
939
Top