A toxic radioactive substance with a density of 4 milligrams per square centimeter is detected in the ventilating of a nuclear processing that was used 55 years ago. If the half-life of the substance is 20 years, what was the density of the substance when it was deposited 55 years ago?
Solution:-
The density of the radioactive substance when it was deposited 55 years ago was approximately 26.9 mg/cm2