After an accident at a nuclear power station, radioactive iodine-131 is released into the air.
Iodine-131 emits beta and gamma radiation. It has a half-life of 8 days.
People living near the power station are told to stay indoors with the windows closed.
Explain why.
Explain why the hazard from contamination by iodine-131 lasts longer than the hazard from being irradiated by a cloud of iodine-131 as it passes overhead.
Calculate the time taken for the activity of the iodine-131 to fall to 116\displaystyle \frac{1}{16}161 of its starting value.
Cows eat grass in the area around the power station. Milk from these cows is not drunk for several weeks after the accident.
Suggest why.