Question

3. The Isotopes of the has half life 5730 years. Fin the Number of year of the after 70% decays. 4. the of a Cach Find Thickness acknin of Cadmium (A=112.4 density=86501 that would attenuate the intensity of a collima thermal neutrons by a factor of 1000. The average abs cross section for " thermal thermal neutrons=3oool. In this problem the sathering cross section in small and you can neglect it. intensity of a collimated beam of so. The average absorpti

Answer 1

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The botopes of 14 has life time 5730 years, Now The decay constant a = .693 ty = .693 5730 fear = 1.2094 xjot year! 30 year Now The decay egnation N= No è dt. - it = ln (A) No= No . The number of years of after 70% decay Co. N = 3 No Noxio ta 1 1,2094 x 14 mm 1 20998107 L (3) = 9955-12 years. The time rehm to 70% decays = 9955.12 years