Question

One gram of a living plant containing Carbon-14, decays at about 16 disintegrations per minute. It is found that one gram of a dead plant decays at 1 disintegration per minute. The half-life of Carbon-14 is about 5500 years. Calculate the probable age of the plant. Thank you.

Answer 1

1 dpm is about 4 half lives from the start = 16 dpm. (16-8-4-2-1). Thus, 4 half-lives X 5500 years = about 22,000 years.

Answer 2

1/16 rate is (1/2)^n where n = # half-lives.
n = 4, so 4 x 5500 = 22,000 years, as @LunarSolstice just found.

Answer 3

Thank you! ^.^