`M_p` denotes the mass of a proton and `M_n` that of a neutron. A given nucleus, of binding energy `B`, contains `Z` protons and `N` neutrons. The mass `M(N,Z)` of the nucleus is given by.

Options

A. `M(N,Z)=NM_n + ZM_P+ Bc^2`
B. `M(N,Z)=NM_n + ZM_P- B//c^2`
C. `M(N,Z)=NM_n + ZM_P+ B//c^2`
D. `M(N,Z)=NM_n + ZM_P- Bc^2`

Answer

B

Explanation

Mass of nucleus is slightly less than sum of masses of its constituents. This mass difference is equivalent to binding energy .
`therefore Deltam=E/C^2=(ZM_P+NM_n)-M(N.Z)`
Hence M (N,Z)=`NM_n+ZM_P-B/C^2`