Question

 In the formula A(t) = A0ekt
, A is the amount of radioactive material
remaining from an initial amount A0 at a given time t, and k is a negative
constant determined by the nature of the material. A certain radioactive isotope
decays at a rate of 0.125% annually. Determine the half-life of this isotope, to the
nearest year

Answer 1

A = A0*2^(t/T)

A/A0 = 1 - 0.00125 = 0.99875

2^(-1/T) = 0.99875
-1/T = ln(0.99875)
T = -1/ln(0.99875)
T = 799.499 years