Half-life problem

Question

A radioactive substance used in nuclear weapons decays at the rate of 3.6% per year. Calculate the half-life of the radioactive substance. (Round to two decimal places as needed)

Answer 1

% remaining after each year: 100 - 3.6 = 96.4%

 

Solve for t in

 

1/2 = (0.964)^t

 

t = log(1/2) / log(0.964) ≅ 18.905 years

 

t_1/2 = 18.905 years