阿摩線上測驗
39.An experiment with 
takes 47.5 hours. At the end of the experiment, 1.90 ng of 
remains. If the half life is 18.0 hours, how many ng of 
were originally present?
(A) 2.47 ng
(B) 3.05 ng
(C) 3.28ng
(D) 11.8 ng
答案：登入後查看
統計： A(10), B(0), C(0), D(1), E(0) #2740050
統計： A(10), B(0), C(0), D(1), E(0) #2740050