I had sworn to give them and they saw any high hill or any leafy tree, there they offered their sacrifices, made offerings that aroused my anger, presented their fragrant incense and poured out their drink offerings.
Smoke alarms contain a weak source made of Americium-241.
Alpha particles are emitted from here, which ionise the air, so that the air conducts electricity and a small current flows.
If smoke enters the alarm, this absorbs the a particles, the current reduces, and the alarm sounds. In paper mills, the thickness of the paper can be controlled by measuring how much beta radiation passes through the paper to a Geiger counter.
The counter controls the pressure of the rollers to give the correct thickness.
With paper, or plastic, or aluminium foil, b rays are used, because a will not go through the paper.
We choose a source with a long half-life so that it does not need to be replaced often.
Some cancers are easier to treat with radiotherapy than others - it's not too difficult to aim gamma rays at a breast tumour, but for lung cancer it's much harder to avoid damaging healthy cells.
Also, lungs are more easily damaged by gamma rays, therefore other treatments may be used.
The age of the ancient organic materials can be found by measuring the amount of Carbon-14 that is left.