The β--activity of a sample of CO2 prepared from a contemporary wood gave a count rate of 25.5 counts per minute (c.p.m.). The same , mass of CO2 from an ancient wooden statue gave a count rate of 20.5 cpm., in the same counter condition. Calculate its age to the nearest 50 year taking t1/2 for 14C as 5770 year. What would be the expected count rate of an identical mass of CO2 from a sample which is 4000 year old?
