(a) Iodine-131 with a half-life of 8.0 days and activity of 8 C may be taken as liquid or in a capsule.(b)Technetium-99 with a half-life of 6 hours gives gamma-rays of 140 ke V energy.(c) Iodine-123 is suitable for medical studies since it gives no beta- radiation.(d) Cobalt-60 sources of up to 10 000 curies have been used; such a source gives 200 R per minute at 1 m. 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.Carbon has unique properties that are essential for life on Earth.Familiar to us as the black substance in charred wood, as diamonds, and the graphite in “lead” pencils, carbon comes in several forms, or isotopes.Here’s an example using the simplest atom, hydrogen. Carbon-14 is an unstable isotope of carbon that will eventually decay at a known rate to become carbon-12.Radiocarbon dating uses isotopes of the element carbon. Cosmic rays – high energy particles from beyond the solar system – bombard Earth’s upper atmosphere continually, in the process creating the unstable carbon-14. Because it’s unstable, carbon-14 will eventually decay back to carbon-12 isotopes.It makes no sense at all if man appeared at the end of billions of years.
When smoke gets into the detector the alpha particles cannot get through to the sensor and the alarm goes off. Sterilisation of food Bacteria in food can be killed if exposed to gamma radiation.7.The unstable or more commonly known radioactive isotopes break down by radioactive decay into other isotopes.Radioactive decay is a natural process and comes from the atomic nucleus becoming unstable and releasing bits and pieces.For geological purposes, this is taken as one year.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.One rare form has atoms that are 14 times as heavy as hydrogen atoms: carbon-14, or C ratio gets smaller.