Question

The half-life of bismuth-210, 210Bi, is 5 days.

(a) If a sample has a mass of 344 mg, find the amount remaining after 15 days.

(b) Find the amount remaining after t days.

I have already found the answer to part a but I cannot get the second part.

Answer 1

whats the answer to the first part? then maybe I can do it.

Answer 2

What you have to do is make an equation for the answer to A. That is then the answer to B.

Answer 3

The initial amount is \(A_0\),
(the half-life is \(t_{1/2}\))
and the amount remaining after a time \(t\), is \(A(t)\)
\[\large A(t) = A_0(\tfrac12)^{t/t_{1/2}}\]

Answer 4

The formula first 5 years, we get 344/2=172
the next 5 years we 172/2=86
the last 5 years we get 86/2 =43