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  2. Isotopes of potassium - Wikipedia

    en.wikipedia.org/wiki/Isotopes_of_potassium

    K. [3] Three of those isotopes occur naturally: the two stable forms 39 K (93.3%) and 41 K (6.7%), and a very long-lived radioisotope 40 K (0.012%) Naturally occurring radioactive 40 K decays with a half-life of 1.248×10 9 years. 89% of those decays are to stable 40 Ca by beta decay, whilst 11% are to 40 Ar by either electron capture or ...

  3. K–Ar dating - Wikipedia

    en.wikipedia.org/wiki/K–Ar_dating

    K (0.0117%), 41 K (6.7302%). 39 K and 41 K are stable. The 40 K isotope is radioactive; it decays with a half-life of 1.248 × 10 9 years to 40 Ca and 40 Ar. Conversion to stable 40 Ca occurs via electron emission in 89.3% of decay events. Conversion to stable 40 Ar occurs via electron capture in the remaining 10.7% of decay events. [3]

  4. Radioactive decay - Wikipedia

    en.wikipedia.org/wiki/Radioactive_decay

    In all of the above examples, the initial nuclide decays into just one product. [37] Consider the case of one initial nuclide that can decay into either of two products, that is A → B and A → C in parallel. For example, in a sample of potassium-40, 89.3% of the nuclei decay to calcium-40 and 10.7% to argon-40. We have for all time t:

  5. Bateman equation - Wikipedia

    en.wikipedia.org/wiki/Bateman_equation

    In nuclear physics, the Bateman equation is a mathematical model describing abundances and activities in a decay chain as a function of time, based on the decay rates and initial abundances. The model was formulated by Ernest Rutherford in 1905 [1] and the analytical solution was provided by Harry Bateman in 1910. [2]

  6. Kaon - Wikipedia

    en.wikipedia.org/wiki/Kaon

    L = K 2 + εK 1. and similarly for K S. Thus occasionally the K L decays as a K 1 with CP = +1, and likewise the K S can decay with CP = −1. This is known as indirect CP violation, CP violation due to mixing of K 0 and its antiparticle. There is also a direct CP violation effect, in which the CP violation occurs during the decay itself.

  7. Electron capture - Wikipedia

    en.wikipedia.org/wiki/Electron_capture

    If the energy difference between the parent atom and the daughter atom is less than 1.022 MeV, positron emission is forbidden as not enough decay energy is available to allow it, and thus electron capture is the sole decay mode. For example, rubidium-83 (37 protons, 46 neutrons) will decay to krypton-83 (36 protons, 47 neutrons) solely by ...

  8. Does the secretary of education need to be an educator? - AOL

    www.aol.com/news/does-secretary-education...

    While Linda McMahon, President-elect Donald Trump's pick for education secretary, is meeting with senators who will determine whether she'll be confirmed for that role, her lack of experience in ...

  9. Half-life - Wikipedia

    en.wikipedia.org/wiki/Half-life

    Rutherford applied the principle of a radioactive element's half-life in studies of age determination of rocks by measuring the decay period of radium to lead-206. Half-life is constant over the lifetime of an exponentially decaying quantity, and it is a characteristic unit for the exponential decay equation. The accompanying table shows the ...