The half-life of a radioactive substance is 15 hours. If at some instance, the sample has a mass of 512 g, calculate the time it will take 78 of the sample to decay by Sunday | Jan 9 | Physics WAEC | 0 comments A. 15 hours B. 30 hours C. 45 hours D. 60 hours Correct Answer: Option C – 45 hours Users Also Read These:A radioactive element has a decay constant of…The half life of a radioactive substance is 14 days.…A radioactive substance of mass 768g has a half-life…The number of protons in an element increased by one…The half-life of a radioactive substance is 2…