12. An initial amount of 100 grams of the radioactive isotope thorium-234 decays according
to
A(t) = 100e^-0.02828t
where t is in years. How long will it be before half of the initial amount has disinte-
grated?
Radioactive half-life An initial amount of 100 g of the radioactive isotope thorium-234 decays according to Q ( t ) = 100 e − 0.02828 t where t is in years.
