1.(a).Present-day plant life has a carbon-14 decay rate of 16 disintegrations per minute (dpm) per gram of carbon. If a contemporary wooden chair were somehow preserved for the next 3,900 years, what 14C decay rate should be expected from the wood used to make the chair? (t1/2 = 5,730 yr)
(b)Rubidium-87 decays by beta decay with a half-life of 4.9 x 10^10 yr. How many 87Rb atoms are in a moon rock sample that has a rubidium decay rate of 3500 disintegrations per hour.