Answer to Question #207411 in Atomic and Nuclear Physics for Charles

Question

in 180 minutes, the activity of a certain radioactive substance falls to 1/8 its original value. calculate its half life

Answer 1

$\frac18N_0=N_02^{-\frac{t}{T_{1/2}}},$ $\implies$

$T_{1/2}=\frac t 3=\frac{180}{3}=60~min.$