A radioactive substance decays exponentially. a scientist begins with 120 milligrams of a radioactive substance. after 14 hours, 60 mg of the substance remains. how many milligrams will remain after 19 hours?
First thing is you have to find the half life of the substance. The half life equation is Final Mass = Initial Mass * 0.5^(time/time per half life) Now we substitute the values given and we get 60 mg = 120 * 0.5^(14/t) Solve for t and you get t = 14 hours Now plug 19 into the equation Final Mass = 120 * 0.5^(19/14) Final Mass = 46.84 mg
