A physicist placed a radioactive source in front of a radiation detector and recorded the count rate every 3 hours. The table below shows the gathered data:
| Time (hours) | Measured count rate (counts per minute) | Corrected count rate (counts per minute) |
|---|---|---|
| 0 | 425 | 400 |
| 3 | 308 | 283 |
| 6 | 225 | 200 |
| 9 | 166 | 141 |
| 12 | 125 | 100 |
| 15 | 96 | 71 |
State two natural sources of background radiation.
Describe how the physicist should measure the background radiation and use it to correct the measured count rates.
Use the data in the table to determine the half-life of the radioactive source.
The radioactive nuclei in the source emit beta-minus (β−\beta^-β−) particles. Describe the effect of this emission on the proton number and mass number of the nucleus.
Describe two safety precautions that should be taken to reduce risks when working with this radioactive source.
