(a) Define the Q–value of a nuclear reaction. (b) A nuclear reaction is said to be…

PHYSICS · Multi-part · A Level · Physics · Nuclear physics · Nuclear physics

Problem

(a) Define the Q–value of a nuclear reaction. (b) A nuclear reaction is said to be exothermic when it releases energy and endothermic when it absorbs energy. Explain, without performing any numerical calculation, how the relative total masses of the reactants and products decide whether the reaction is exothermic or endothermic. (c) Two reactions are listed below: (i) 12H+  12H  ⟶  23He+  01n_1^2\text H +\;_1^2\text H \;\longrightarrow\;_2^3\text{He}+\;_0^1\text n (ii) 01n+  92235U  ⟶  3692Kr+  56141Ba+3 01n_0^1\text n +\;_{92}^{235}\text U\;\longrightarrow\;_{36}^{92}\text{Kr}+\;_{56}^{141}\text{Ba}+3\,_0^1\text n Using qualitative reasoning based on binding–energy per nucleon and mass–energy equivalence, discuss which of the above reactions releases more energy per nucleon. (d) State any two practical consequences of the sign and magnitude of the Q–value in nuclear engineering applications. (i)  12H+  12H  ⟶    23He+  01n\,_{1}^{2}\text{H} + \;_{1}^{2}\text{H} \;\longrightarrow\; \;_{2}^{3}\text{He} + \;_{0}^{1}\text{n} (ii)  01n+  92235U  ⟶    3692Kr+  56141Ba+3 01n\,_{0}^{1}\text{n} + \;_{92}^{235}\text{U}\;\longrightarrow\; \;_{36}^{92}\text{Kr} + \;_{56}^{141}\text{Ba} + 3\,_{0}^{1}\text{n} Using qualitative reasoning based on binding–energy per nucleon and mass–energy equivalence, discuss which of the above reactions releases more energy per nucleon. (a) Define the Q–value of a nuclear reaction. (b) A nuclear reaction is said to be exothermic when it releases energy and endothermic when it absorbs energy. Explain, without performing any numerical calculation, how the relative total masses of the reactants and products decide whether the reaction is exothermic or endothermic. (c) Two reactions are listed below: (i)  12H+  12H  ⟶    23He+  01n\,_{1}^{2}\text{H} + \;_{1}^{2}\text{H} \;\longrightarrow\; \;_{2}^{3}\text{He} + \;_{0}^{1}\text{n} (ii)  01n+  92235U  ⟶    3692Kr+  56141Ba+3 01n\,_{0}^{1}\text{n} + \;_{92}^{235}\text{U}\;\longrightarrow\; \;_{36}^{92}\text{Kr} + \;_{56}^{141}\text{Ba} + 3\,_{0}^{1}\text{n} Using qualitative reasoning based on binding–energy per nucleon and mass–energy equivalence, discuss which of the above reactions releases more energy per nucleon. (d) State any two practical consequences of the sign and magnitude of the Q–value in nuclear engineering applications.

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