There are many natural occurring radioactive isotopes. Amongthem, Radon(222Rn), 40K and 14C are the most important ones.
a) Where are/ were these isotopes produced and come from? Youcan consult Wikipedia for this question and briefly describe wherethey come from
b) Consider a person of 70 Kg. 0.20% of the body mass ispotassium and it is a vital nutrient. Natural potassium (mostly 39Kand 41K) also contains 0.012% 40K with a half- life time of 1.3billion years. 40K emits a β- of average energy of 58.5 keV in89.3% of its decays and a 1.461 MeV γ-ray in 10.7% of the decays.How many of these high-energy γ-rays is generated in the person persecond?
c) If you assume that all the energy from the electrons andγ-rays is absorbed in the body, what is the effective dose for theperson in one year?
d) While nowadays 0.012% of all potassium is 40K, what was itsshare of all potassium 4.5 billion years ago, when the Earthformed?
