# The isotope Francium 224 has a half life of 20 minutes. A sample of the isotope has an initial activity of 9-- disintegrations s^-1. The approximate activity of the sample an hour later will be what? Multiple choice question. Please explain why for answer

May 12, 2017

The number of disintegrations is ${A}_{0} / 8$

#### Explanation:

The half life is $T = 20 m n$

The time is $t = 60 m n$

So, we have $3$ half life, the activity will be multuplied by $\frac{1}{8}$

The number of disintegrations is ${A}_{0} / 8$