These materials have a variety of uses and a selection of these are listed below.(a) dating geological specimens, using uranium, rubidium or bismuth; (b) dating archaeological specimens, using carbon 14(c) paper or plastic thickness measurement using beta radiation(d) treatment of tumours;(e) sterilisation of foodstuffs;(f) nuclear pacemakers for the heart;(g) liquid flow measurement;(h) tracing sewage or silt in the sea or rivers;(i) checking blood circulation and blood volume;(j) atomic lights using krypton 85;(k) checking the silver content of coins;(I) radiographs of castings and teeth;(m) testing for leaks in pipes;(n) tracing phosphate fertilisers using phosphorus 32(o) smoke alarms (p) sterilisation of insects for pest control.(a) Geological dating The dating of rocks is carried out using the decay of uranium 238 (half life 4.5x10 years).One assumption is that the global levels of carbon 14 (also called radiocarbon) in the atmosphere has not changed over time.The other assumption is the corollary of the first; the biosphere has the same overall concentration of radiocarbon as the atmosphere due to equilibrium.
Bacteria in food can be killed if exposed to gamma radiation.There are two human activities recognized to have irreparably changed the global radiocarbon levels—the burning of fossil fuel and nuclear weapons testing.Burning of large quantities of fossil fuels like coal, referred as the Suess effect, had significantly lowered the radiocarbon concentration of the atmospheric carbon reservoir.The very long half-lives of these isotopes make them particularly suitable for finding the age of rocks.
For example if you consider the uranium series that the final stable isotope is lead-206, and if we assume that there was no lead in the rock when it was formed the ratio of the number of atoms of lead 206 (N The carbon 14 is then absorbed by plants; these in turn are eaten by animals which may then be eaten by other animals.
Therefore A = A If a little radioactive material is put into a moving liquid the path of this liquid can be tracked.