Physics

Physics

Problem

An α\alpha-decay process is represented schematically as  92238U  →   90234Th+ 24He.^{238}_{\ 92}\text{U} \;\rightarrow\; ^{234}_{\ 90}\text{Th} + ^{4}_{\ 2}\text{He}. The following nuclear masses are given:  92238U:238.050788 u^{238}_{\ 92}\text{U}: 238.050788\,\text{u},  90234Th:234.043593 u^{234}_{\ 90}\text{Th}: 234.043593\,\text{u},  24He:4.002603 u^{4}_{\ 2}\text{He}: 4.002603\,\text{u}. (Atomic-electron masses are already included in these tabulated values.) a. (a) Write the numerical value of the total mass of the decay products and hence find the mass defect ΔM\Delta M for the decay. b. (b) Calculate the energy (in MeV) released in this α\alpha-decay. Use 1 u=931 MeV1\,\text{u}=931\,\text{MeV}. c. (c) Briefly state how this released energy is shared between the emitted α\alpha-particle and the recoiling thorium nucleus.

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