# HW6-20 - 5-14 Radioactivity Chap. 5 20. Charcoal found in a...

This preview shows page 1. Sign up to view the full content.

This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 5-14 Radioactivity Chap. 5 20. Charcoal found in a deep layer of sedimentin a caveis found to have an atomic 14Cj12Cratio only 30% that of a charcoal sample from a higher level with a known age of 1850y. What is the age of the deeperlayer? Solution: Let R denote the atomic ratio of 14Cto 12C.We assumethe same initial ratio was incorporated into both layers when they were formed, i.e., Rd(O)= Rh(O). Then the present ratio in the deeper layer to that in the higher layer is 1 td =th -~ln [~ ~(td) (P5.8) For 14C, ). = In2/Tl/2 = 1.21 x 10-4 y-l, and for the given information that R(td)/R(th) = 0.30 and th = 1850y, Eq. (P5.8) gives the desired age as td = 1850 -41n(0.30) 1.21 x 10- 1 = 11,800 y. July 24, 2002 ...
View Full Document

## This note was uploaded on 02/01/2010 for the course ECE 4130 taught by Professor Cady during the Spring '06 term at Cornell University (Engineering School).

Ask a homework question - tutors are online