Radioactive dating examples in present day news articles regarding traditional dating
Most scientists and many Christians believe that the radiometric dating methods prove that the earth is 4.5 billion years old.
Different isotopes have different half-lives and sometimes more than one present isotope can be used to get an even more specific age of a fossil.
Perhaps the most widely used evidence for the theory of evolution through natural selection is the fossil record.
The fossil record may be incomplete and may never fully completed, but there are still many clues to evolution and how it happens within the fossil record.
After two half-lives, another half of your leftover Carbon-14 would have decayed into Nitrogen-14.
Half of 50% is 25%, so you would have 25% Carbon-14 and 75% Nitrogen-14.
The best radioactive element to use to date human fossils is Carbon-14.