A student is carrying out an experiment to measure the radiation from a radioactive source.
She uses a radiation detector and records the total counts in 4-minute intervals. She does this three times with the source present and three times with the source absent. Here are her results:
| Total counts in 4 minutes with source present | Total counts in 4 minutes with source absent |
|---|---|
| 138 | 58 |
| 144 | 62 |
| 138 | 60 |
What is the average corrected count rate for the source?
15 counts / minute
20 counts / minute
35 counts / minute
80 counts / minute
484 exam-style questions on CIE IGCSE Physics 5.2 Radioactivity, covering 5.2.1 Background radiation and measuring count rate, 5.2.2a Alpha, beta and gamma emission, 5.2.2b Deflection and ionising effects of nuclear radiation, 5.2.3a Radioactive decay, 5.2.3b Effects of decay on the nucleus and decay equations, 5.2.4a Half-life, 5.2.4b Choosing isotopes for applications, and 5.2.5 Effects of ionising radiation and safety precautions. Each one has a worked solution and a mark scheme showing where the marks go.