Some substances give out radiation all the time, whatever is done to them. These substances are said to be radioactive. Radioactivity occurs as a result of changes in the of atoms (nuclear changes). When an unstable nucleus splits up (disintegrates): it emits ; a atom, with a different number of protons, is formed. There are radioactive substances all around us, including in the ground, in the air, in building materials and in food. Radiation also reaches us from space. The radiation from all these sources is called radiation.
There are radioactive substances all around us, including in the ground, in the air, in building materials and in food. Radiation also reaches us from space. The radiation from all these sources is called radiation.
The background radiaion from 'Nuclear power & weapons' is from the fallout from the nuclear bomb tests and accidents in power stations, rather than the 'unused bombs' and nuclear fuel that is correctly stored.
When conducting experiments we must measure the background radiation and take it away from our results. In order for this to give results with an acceptable degree of accuracy, the background radiation should be no more than 10% of the activity.
