If `M(A,Z)`, `M_(p)and M_(n)` denote the masses of the nucleus `._(Z)X^(A)`, proton and neutron respectively in units of U (where`1U=931MeV//c^(2)`) and B.E. represents its B.E. in MeV, then

Options

A. M( A , Z) = `ZM_(p) + (A - Z) M_(n) - BE//c^(2)`
B. `M(A , Z) = ZM_(p) + (A - Z) M_(n) + BE`
C. `M(A , Z) = ZM_(p) + (A - Z) M_n - BE`
D. `M (A , Z) = ZM_(p) + (A - Z) M_(n) + BE//c^(2)`

Answer

A

Explanation

Mass defect = `ZM_(P) + (A - Z) M_(n) - M (A ,Z)` or `, (B.E.)/(c^(2)) = ZM_(p) + (A - Z) M_(n) - M (A, Z)`
`therefore M (A , Z) = ZM_(p) + (A - Z) M_(n) - (B.E.)/(c^(2))`