Homework Statement
The decay constant of xenon-142 is 0.462(s^-1), and the decay constant of strontium-90 is 7.85*10^-10 (s^-1). Initially, a sample of radioactive waste material contains equal numbers of strontium-90 and xenon-142 nuclei.
Calculate the time taken for the ratio: number...
Homework Statement
The half life of strontium-90 is 28.0 years. Deduce that the decay constant of strontium-90 is 7.85 * 10^(-10) s^1.
Homework Equations
k = ln 2 over half-life in seconds
The Attempt at a Solution
dunno...please help me solve this!