Match List-I with List-II.
| List-I | List-II |
|---|---|
| (A) Mass defect of a nucleus | (I) \(\Delta M\,c^{2}\) |
| (B) Atomic mass unit, 1 u | (II) \([Zm_p+(A-Z)m_n]-M\) |
| (C) Binding energy of a nucleus | (III) Final kinetic energy – initial kinetic energy |
| (D) Q-value of a nuclear process | (IV) \(\frac{1}{12}\) of the mass of one \({}^{12}\mathrm{C}\) atom |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → (A)-(II), (B)-(IV), (C)-(I), (D)-(III)
(A) Mass defect of a nucleus — This matches (II). The mass \( M \) of a nucleus is less than the total mass of its \( Z \) protons and \( (A-Z) \) neutrons. This difference is the mass defect.
(B) Atomic mass unit, 1 u — This matches (IV). The atomic mass unit is defined from the carbon-12 atom and is about \( 1.66\times10^{-27}\ \mathrm{kg} \).
(C) Binding energy of a nucleus — This matches (I). The mass defect, changed into energy by \( E=mc^{2} \), is the energy needed to break the nucleus into its nucleons.
(D) Q-value of a nuclear process — This matches (III). The Q-value is the kinetic energy gained in the process. It is also equal to the loss of mass multiplied by \( c^{2} \).
NCERT (2026-27):
Summary – “7. … The difference in mass of a nucleus and its constituents is called the mass defect, ΔM = (Z mp + (A – Z )mn) – M”
Atomic Masses and Composition of Nucleus – “… This unit is the atomic mass unit (u), defined as 1/12th of the mass of the carbon (12C) atom. …”
Summary – “Using Einstein’s mass energy relation, we express this mass difference in terms of energy as ΔEb = ΔM c2 The energy ΔEb represents the binding energy of the nucleus. …”
Summary – “9. The Q-value of a nuclear process is Q = final kinetic energy – initial kinetic energy. …”