Posted by Beth on Friday, July 27, 2012 at 5:17pm.
How many halflives are required for the number of radioactive nuclei to decrease to 1/10^4 of the initial number?

Physics  drwls, Saturday, July 28, 2012 at 3:42am
Let N be the number of halflives.
(1/2)^N = 10^4
N log(0.5) = log(10^4)
0.30103 N = 4
N = 13.29 halflives