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|Published on: Jan 9|Categories: 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:If the decay constant of a radioactive substance is…The half-life of a radioactive element is 5.…A radioactive substance has a half-life of 20 hours.…What is the decay constant of a radioactive element…A radioactive element has a decay constant of…SEE ALSO A galvanometer with a full-scale deflection of 20 mA is Converted to read 8 K by connecting a 395 Ω resistor in series with it. Determine the internal resistance of the galvanometer