a) Consider a person of 70 Kg. 0.20% of the body mass is potassium and it...

a) Consider a person of 70 Kg. 0.20% of the body mass is potassium and it is a vital nutrient. Natural potassium (mostly ³⁹K and ⁴¹K) also contains 0.012% ⁴⁰K with a half- life time of 1.3 billion years. ⁴⁰K emits a β- of average energy of 58.5 keV in 89.3% 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 per second?

b) If you assume that all the energy from the electrons and γ-rays is absorbed in the body, what is the effective dose for the person in one year?

c) While nowadays 0.012% of all potassium is ⁴⁰K, what was its share of all potassium 4.5 billion years ago, when the Earth formed?

Expert Solution

gladiator answered 5 months ago

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