# Homework Help: Radiocarbon dating of a piece of wood

1. Mar 11, 2012

### Lindsayyyy

Hi

1. The problem statement, all variables and given/known data

A lance of wood is found wheres one piece contains 2,70 g 12^C. A scintillation counter shows 27,3 radiactive decay per minute.

How old is the lance?

2. Relevant equations

$$N(t)= N_0 \cdot e^{-\lambda t}$$

maybe half life of 14^C : 5730 years.

3. The attempt at a solution

My attempt was using the above equation, I have nothing else given (like mass of a C atom etc). My problem is I think I am missing some information. I tried to get to the solution by using the relative ratio of 12C and 14C but I read that this only counts for living organisms. Is it even possible to solve this without any further information? Sorry for such a short attempt at a solution but I have no idea, wasn't even able to find something which helps me and I really like to understand that problem.

1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Mar 11, 2012

### Staff: Mentor

It looks like the problem is solvable if you take in to account an assumption of the original ratio of C14 to C12. The measured decay rate should tell you the current number of atoms of C14 remaining in the sample.

3. Mar 11, 2012

### Office_Shredder

Staff Emeritus
One example of a living organism is the tree that the wood came from

4. Mar 12, 2012

### Lindsayyyy

but wood is a "dead" organism :). I though I am not allowed to use that information for dead objects. I think I can solve it than, thanks.

5. Mar 12, 2012

### Staff: Mentor

Wood is dead as soon as the tree dies. That's when its radiocarbon clock starts ticking, as the "living" C14/C12 ratio is no longer maintained by constant replenishment though metabolism.