Two stable nuclei

PHYSICS · Single correct · CBSE · Physics · Nuclei · Nuclei

Problem

Two stable nuclei,

P

and

Q

, each have mass number

A=40

. For

P

, the atomic number is

Z_P = 18

; for

Q

Z_Q = 20

. Their measured nuclear masses are equal:

M_P = M_Q = 39.962\,\text{u}

. Using

m_p = 1.007276\,\text{u}

and

m_n = 1.008665\,\text{u}

, which statement about their mass defects is correct? (a)

\Delta M_P = \Delta M_Q

(b)

\Delta M_P < \Delta M_Q

(c)

\Delta M_P > \Delta M_Q

(d)

\Delta M_P > \Delta M_Q\;\text{but by less than}\;1\times10^{-3}\,\text{u (effectively equal)}