A radioactive source produces a count rate on a detector of 2400 counts/s2400\text{ counts/s}2400 counts/s. After 60 hours60\text{ hours}60 hours, the count rate has fallen to 75 counts/s75\text{ counts/s}75 counts/s. Both count rates have been corrected for background radiation. What is the half-life of the source?
144 exam-style questions on CIE IGCSE Physics 5.2.4a Half-life. Each one has a worked solution and a mark scheme showing where the marks go.