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
44 exam-style questions on CIE IGCSE Physics 5.2.1 Background radiation and measuring count rate. Each one has a worked solution and a mark scheme showing where the marks go.