In one complete proton–proton chain inside the Sun

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

Problem

In one complete proton–proton chain inside the Sun, the following reactions occur: (1) 1 ⁣H+1 ⁣H→2 ⁣D+e++ν^1\!\mathrm H + {}^1\!\mathrm H \rightarrow {}^2\!\mathrm D + e^{+}+\nu Q1=0.42 MeVQ_1 = 0.42\,\text{MeV} (2) 2 ⁣D+1 ⁣H→3 ⁣He+γ^2\!\mathrm D + {}^1\!\mathrm H \rightarrow {}^3\!\mathrm He + \gamma Q2=5.49 MeVQ_2 = 5.49\,\text{MeV} (3) 3 ⁣He+3 ⁣He→4 ⁣He+2 1 ⁣H^3\!\mathrm He + {}^3\!\mathrm He \rightarrow {}^4\!\mathrm He + 2\,{}^1\!\mathrm H Q3=12.86 MeVQ_3 = 12.86\,\text{MeV} Steps (1) and (2) each happen twice before step (3) occurs once. Neglecting energy carried away by neutrinos, the total energy released when four protons finally form one helium-4 nucleus is (a) 26.7 MeV26.7\,\text{MeV} (b) 18.8 MeV18.8\,\text{MeV} (c) 24.7 MeV24.7\,\text{MeV} (d) 37.5 MeV37.5\,\text{MeV}

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