The difference in mass of 7X nucleus and the total mass of its constituent nucleons is 0.021 u. The binding energy per nucleon for this nucleus is
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 2.794 MeV
The mass difference between the separate nucleons and the nucleus is the mass defect. Converted to energy with 1 u = 931.5 MeV, it gives the total binding energy, which is then shared among the A = 7 nucleons.
\( E_b = \Delta m \times 931.5\,\mathrm{MeV\,u^{-1}} \)
\( E_b = 0.021\,\mathrm{u} \times 931.5\,\mathrm{MeV\,u^{-1}} \approx 19.56\,\mathrm{MeV} \)
\( \displaystyle \frac{E_b}{A} = \frac{19.56\,\mathrm{MeV}}{7} \)
\( \displaystyle \frac{E_b}{A} \approx 2.794\,\mathrm{MeV} \)