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Radioactive Decay
• Natural process
• Using Carbon 14 as an
example:
– By emitting an electron
and an anti-neutrino,
carbon-14 (half life of
5730 years) decays
into the stable, nonradioactive isotope
nitrogen-14.
Half Life
• Defined in terms of
probability
• Time when the
expected value of the
atoms that have
decayed is equal to
half the original
number
• Different atoms have
different half lives
Half Lives of Atoms
• Carbon 14 has a half
life of 5730 years
• Carbon 14 is used for
fossils, rocks, or
artifacts less than
60,000 years old
• Other atoms have
much longer half lives