Hi, I'm new to the forum and came here because I could use some help. At the moment I am really confused because I know that A = DecayConstant * N, where A is activity and N is the number of atoms before decay. Isn't the Activity is how many atoms decay after 1 second with a specific value of N? So if the DecayConstant = 0.5, N will half each second. So I figured if the DecayConstant is 0.5 then the half life (T1/2) is 1 second. But then I realized that contradicts the following equation: DecayConstant = ln(2) / T1/2, if T1/2 = 1 then DecayConstant = ln(2) =/= 0.5 What have I done wrong and why isn't any of this making sense? Did I make a basic error or do I have poor understanding? Thank you for reading and helping.