Q157 / 160 · TS EAMCET 2021 (06 Aug Shift 2) · Physics
Which one of the following statement is correct?
- Correct answerAThe mass of the nucleus must be less than the sum of the masses of the constituent neutrons and protons.
- BThe mass of the nucleus must be equal to the sum of the masses of the constituent neutrons and protons.
- CThe mass of the nucleus must be greater than the sum of the masses of the constituent neutrons and protons.
- DThe mass of the nucleus must be equal to only the masses of the constituent neutrons or protons.
Solution
The nuclei inside the nucleus are very strongly bound and energies of few $\mathrm{MeV}$ are needed to separate a nucleon from the nucleus. Hence, a minimum energy is required to split the protons and neutrons and that energy is known as the binding energy of the nucleus. If, there are $Z$ number of protons and $N$ number of neutrons and mass of the nucleus is $M(A, Z)$, then binding energy $E_B=Z m_p C^2+N m_n C^2-M(A, Z) C^2>0$, where $m_p$ and $m_n$ are the masses of protons and neutrons, respectively.
Hence, we can conclude that, the mass of the nucleus must be less than the sum of the masses of the constituent neutrons and protons.
Hence, the correct answer is option: 'A'.