An environmental engineer uses a radioactive tracer, sodium-24, to track the flow of groundwater through an underground channel.
Beta-plus (β+\beta^+β+) radiation consists of:
A. electromagnetic waves B. helium nuclei C. high-speed positrons D. protons
State what is meant by the term half-life of a radioactive isotope.
The engineer injects a solution containing sodium-24 into an entry well. Detectors placed at ground level above the aquifer detect the emitted gamma rays to track the path of the water. Suggest why isotopes that emit only alpha radiation are unsuitable for this underground tracking technique.
Sodium-24 has a half-life of 15 hours15\text{ hours}15 hours.
A sample of sodium-24 has an initial activity of 480 MBq480\text{ MBq}480 MBq.
Explain why the activity of any radioactive sample reduces over time.
Calculate the activity of the sodium-24 sample after 60 hours60\text{ hours}60 hours.