Hello!
The half-life is the time of half-disintegration, it is the time in which half of the atoms of an isotope disintegrate.
We have the following data:
mo (initial mass) = 20 g
m (final mass after time T) = 5 g
x (number of periods elapsed) = ?
P (Half-life) = ? (in minutes)
T (Elapsed time for sample reduction) = 8 minutes
Let's find the number of periods elapsed (x), let us see:
Now, let's find the half-life (P) of the radioactive sample, let's see:
I Hope this helps, greetings ... DexteR! =)