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B4. The average peach contains 0.285 g of potassium, and 0.012% (number fraction) of naturally occurring potassium is potassium-40, which has a half-life of 1.248 x 10 years. The mean atomic mass of natural potassium is 39.0983 u. (a) What is the activity of a freshly picked peach? Use 365.25 days for one year and express your answer in Becquerels. (4 marks) (6) Given that potassium has an atomic number of 19 and that potassium-40 undergoes beta-minus decay, determine the atomic number and nucleon number of the isotope that is produced when potassium-40 decays. (2 marks) (c) Calculate the rate of energy released (in MeV/s) due to the beta-minus decay of potassium in a freshly picked peach. The mass of a neutrino or antineutrino is negligible. If you did not obtain an answer for (a), use 9.30 Bq. (4 marks) Some Atomic Masses: A Z Element Atomic Mass 35 17 C1 34.968 853 u 37 17 C1 38 18 Ar 36.965 903 u 37.962 732 u 39.962 383 u 40 Ar : 18 19 39 K 38.963 706 u 39.963 998 u 40 19 K 40 20 Ca 42 20 Ca 39.962 591 u 41.958 618 u 44.955 908 u 45 21 Sc