physics point

                                             Nuclear Decay s The nuclear decay can be divided into three categories α-decay: spontaneous emission of α-particle from a nucleus of large atomic number. This sets an upper limit of atomic numbers of chemical elements occurring in nature.   β-decay: spontaneous emission or absorption of an electron or positron by a nucleus. This tells about the nature of forces. γ-decay: spontaneous emission of high energy photons when nucleus makes transition from excited state to ground state.. Velocity and Energy of alpha-particles (Doubly charged 2 He 4 ): 1.   Determination of velocity and energy of α-particles made it possible to determine energies which differ only in small amounts and this led to the discovery that some radionuclides actually emit spectrum of α-particles. 2.   Knowledge of energies helped to ...