FREE Preview   Half-life is the concept of time required for
half of radioactive isotope s nuclei to decay. The amount
remaining is calculated as the (initial amount) (1/2) (# of 1/2
lives)^n in which the number of 1/2 lives is equal to the time
elapsed over the length of half-life.   It might be wondering if
some, is there's any radioactive on this earth constantly
spontaneously decaying how do we actually still have radioactive
isotopes if our earth is billions millions of years old? Well
actually they take a long time for things to decay doesn't
happen instantly sometimes it does but sometimes they happens
every millions of years such as uranium takes milli- the half
life of uranium takes millions of years meaning that when the
year started we had a certain amount and now we had after 4.5 I
think billion years and million years it's half of the volume
uranium is actually left on this earth so what do I mean by half
life? So half life is the time required for half of the
radioisotopes nuclei to decay.  So l