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Define mass defect and nuclear binding energy. For a nucleus ""_(Z)^(A)X, write the value of mass defect and nuclear binding energy. |
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Answer» If `Deltam` is the mass defect, then Binding energy, `B.E.=Deltam C^(2)` (in joule) `=Zm_(p)+(A-Z)M_(n)-M_("nucleus")` Ifmass defect is in a.m.u. then `B.E.=(Deltamxx931.5)` M EV Expression for binding energy. The mass defect `(Deltam)` OFA nucleus containing Z protons and (A-Z) neutrons is given by `Deltam=ZM_(p)+(A-Z)M_(n)-M_("nucleus")` ...(1) where m is mass of the nucleus. So `M_("nucleus")=(ZM_(p)+(A-Z)M_(n))-DELTA m` ...(2) Since mass of atom `M(""_(Z)X^(A))` is given by `M=M_("nucleus")+ZM_(e)` Using eq (2), we get `M=(ZM_(p)+(A-Z)M_(n))-Deltam+ZM_(e)` `:.` Mass defect, `Deltam=Z(M_(p)+M_(e))+(A-Z)M_(n)-M` `=ZM_(H)+(A-Z)M_(n)-M [ :.M_(p)+M_(e)=M_(H)]` `:.B.E.=Delta mc^(2)` or `B.E.=[ZM_(H)+(A-Z)M_(n)-M]c^(2)` |
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