Carbon-14 undergoes a beta (b) decay with a half-life of 5730 years. a sample of carbon dioxide isolated from the atmosphere was observed to have 13.6 disintegrations per minute. however, a sample of atmospheric methane (containing the same number of carbon atoms) was observed to have 11.1 disintegrations per minute (assume that all of the carbon in the carbon dioxide sample is "fresh" carbon. "fresh'" meaning that the amount of 14c atoms in the sample has not fallen from the steady-state value for all living things in the environment) why is there a lower rate of beta decay in the methane sample? a. b. a similar sample of methane was isolated from a section of permafrost in the canadian tundra and found to have 3.1 disintegrations per minute. how long ago did that section freeze? 0.693 hint: recall that half-life, l/- -and k is the rate constant for the decay. 1/ 2 also remember that the general form of exponential decay is n- n, exp-kt) where n is the amount of "c at any given time (t) no is the original amount of 4c