Nuclei - Result Question 33

34. A nucleus $ _Z^{A} X$ has mass represented by $M(A, Z)$. If $M_p$ and $M_n$ denote the mass of proton and neutron respectively and B.E. the binding energy in $MeV$, then

(a) B.E. $=[Z M_p+(A-Z) M_n-M(A, Z)] c^{2}$

[2007]

(b) B.E. $=[ZM_p^{p}+ZM-M_n^{n}(A, Z)] c^{2}$

(c) B.E. $=M(A, Z)-Z M_p-(A-Z) M_n$

(d) B.E. $=[M(A, Z)-Z M_p-(A-Z) M_n] c^{2}$

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Answer:

Correct Answer: 34. (a)

Solution:

  1. (a) The difference in mass of a nucleus and its constituents, $\Delta M$, is called the mass defect and is given by

$\Delta M=[Z M_p+(A-Z) M_n]-M$

and binding energy $=\Delta M c^{2}$

$=[{Z M_p+(A-Z) M_n}-M] c^{2}$