How can half-life be described in terms of radioactive decay?

1 Answer

It is the time taken for the intensity of the radioactive emission to decay to half of its original intensity.

Explanation:

This is by definition.
Most radioactive decay follows the natural logarithmic law, ie

I(t)=I0eλt

Lamda is a constant which differs for different radioactive materials and that is why each on has a different half life.
So the half life is the time taken for I to reach exactly half of I0, ie

t=t12I=12I0