The half-life for radioactive decay of 14C is 5730 years. An archeological artifact containing wood had only 80%of the 14C found in a living tree. Estimate the age of the sample.

Radio active decay occurs via first order rate law,

t1/2 = 5730 years. rate constant(k) of given decay is 0.693/t1/2


0.693/5730 = 1.2 × 10-4 year-1


By first order integrated rate law age of sample will be,



where T is the age of sample A0 is the initial activity of the sample. and At is the activity of sample at any time t.



T = 0.18 × 104 years.


Age of given sample is 0.18 × 104 years.


14