A radioactive source has a half-life of 4 days. A detector near the source shows a reading of 8000 counts per minute. Background radiation can be ignored. What is the reading on the detector 12 days later?
1000 counts per minute1000\text{ counts per minute}1000 counts per minute
2000 counts per minute2000\text{ counts per minute}2000 counts per minute
2667 counts per minute2667\text{ counts per minute}2667 counts per minute
4000 counts per minute4000\text{ counts per minute}4000 counts per minute
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.