CBSE 2025 · Region 7 · Set 2 · Q21 · 2 marks
Calculate the binding energy per nucleon (in MeV ) of a helium nucleus ( $\displaystyle { }_{2}^{4} \mathrm{He}$ ) . Given: $\displaystyle \mathrm{m}\left({ }_{2}^{4} \mathrm{He}\right)=4 \cdot 002603 \mathrm{u}$ \[\begin{aligned} & \mathrm{m}_{\mathrm{n}}=1.008665 \mathrm{u} \\ & \mathrm{~m}_{\mathrm{H}}=1.007825 \mathrm{u} \\ & 1 \mathrm{u}=931.5 \mathrm{MeV} / \mathrm{c}^{2} \end{aligned} \]
Marking-scheme solution
\(\displaystyle \Delta \mathrm{m}=\left(2 \mathrm{m}_{\mathrm{n}}+2 \mathrm{m}_{\mathrm{H}}\right)-\mathrm{m}\left({ }_{2}^{4} \mathrm{He}\right) =2 \times 1.008665+2 \times 1.007825-4.002603 =0.0303774 \mathrm{u}\) \(\displaystyle B E=\Delta \mathrm{m} \mathrm{c}^{2} =0.030377 \times 931 =28.2962 \mathrm{MeV}\) \(\displaystyle \frac{\mathrm{BE}}{\text { nucleon }}=\frac{28.2962}{4}=7.07 \mathrm{MeV}\)
NucleiMass-Energy and Nuclear Binding EnergyApplyvery_short_answermedium
More from Nuclei
- Explain the terms mass defect and binding energy. How are they related?2026 · asked 3×
- (i) Prove that the nuclear density is same for all nuclei. (ii) Draw a plot of potential energy of a pair of…2023 · asked 3×
- Differentiate between nuclear fission and nuclear fusion. Give one example for each with nuclear reaction.2026 · asked 3×
- Assertion: The binding energy per nucleon is practically constant for mass number in the range ( 30<A<170 ).…2025 · asked 3×
- (i) Write any two features of nuclear forces. (ii) If both the number of protons and the neutrons are…2026 · asked 3×
- Assertion: During formation of a nucleus, the mass defect produced is the source of the binding energy of the…2025 · asked 3×
- Which of the following statements is not true for nuclear forces?2023 · asked 3×
- Calculate the energy released in MeV in the following reaction: 1^2 H+ 1^3 H → 2^4 He+n Given: m( 1^2…2022 · asked 3×
CBSE Class 12 Physics past-paper question from the 2025board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.