calculate the radioactivity of the initial time for a neutron source has 1mg 252Cf

1. Because the content of 14C within a living organism is the same as the content of the 14C in atmosphere

and 14C content begins to change after metabolism once stopped, therefore archaeologists use 14C

radioactive decay to determine the age of organism in paleontology. It is possible to determine the age of

organism in accordance with existing paleontological amount of 14C. If known 14C decay constant À is

0.00012097/year and 14C content of a paleontology fossil is measured as 5% of the content of the 14C in

atmosphere, how many years ago did this creature die?