Question

The half life for radioactive decay of .14C is 5730 years. An archaeological artifact containing wood had only 80% of the .14C found in a living tree. Estimat the age of the sample. Select the correct answer from above options

Answer 1

Correct Answer - 1845 years N N0 =80%or0.80 t1/2=5730years k= 0.693 t1/2 = 0.693 5730years =1.21×10-4year-1 k= 2.303 t log N0 N 1.21×10-4= 2.303 t log 1 0.8 T= 2.303 1.21XX104 log1.25 = 2.303 1.21×10-4 log1.25 = 2.303 1.21×10-4 ×0.0969=1845years Alternatively Use direct relation, t80% t1/2 = log(100) 80 0.3 t80%= 5730years×log0.8 0.3 ≈1845years.