Question

A radioactive element decays exponentially according to the function Q(t) = Q0ekt
.If 100 mg of the element decays to 25 mg in 12 days, find the half-life of the element.


please help

Answer 1

NEvermind got it its 6

Answer 2

100 * 1/2 * 1/2 = 25

12 days = 2 half lives

OR

1/4 = e^(12k)

ln(1/4) = 12 k

[ln(1/4)] / 12 = k


ln(1/2) = k t

t = ln(1/2) / {[ln(1/4)] / 12} = 6