The proton–proton (p, p) cycle in the Sunसूर्य में प्रोटॉन–प्रोटॉन (p, p) चक्रThe proton–proton (p, p) cycle in the Sun
NCERT Eq. 13.14–13.15 · Class 12 Physics · Chapter 13 · interactive diagram
Read Chapter 13 with this diagramइस डायग्राम के साथ अध्याय 13 पढ़ेंIs diagram ke saath Ch 13 padhiyeAll Physics diagramsसभी भौतिकी डायग्रामSaare Physics diagrams
Parts and what they mean
- (i) ¹H + ¹H → ²H + e⁺ + ν + 0.42 MeV ((i) ¹H + ¹H → ²H + e⁺ + ν + 0.42 MeV) — Two protons form a deuteron; one proton changes into a neutron, giving out a positron and a neutrino.
- (ii) e⁺ + e⁻ → γ + γ + 1.02 MeV ((ii) e⁺ + e⁻ → γ + γ + 1.02 MeV) — The positron meets an electron; they annihilate into two gamma photons (2 × 0.511 MeV).
- (iii) ²H + ¹H → ³He + γ + 5.49 MeV ((iii) ²H + ¹H → ³He + γ + 5.49 MeV) — The deuteron captures a proton to make light helium, ³He.
- (iv) ³He + ³He → ⁴He + ¹H + ¹H + 12.86 MeV ((iv) ³He + ³He → ⁴He + ¹H + ¹H + 12.86 MeV) — Two ³He nuclei (so (i)–(iii) happen twice) make ordinary helium and give back two protons.
- Net result (कुल परिणाम) — 2(i) + 2(ii) + 2(iii) + (iv): 2(0.42) + 2(1.02) + 2(5.49) + 12.86 = 26.72 ≈ 26.7 MeV. Four hydrogen atoms → one helium atom.
Original diagram drawn by Simple Learning Hub, based on NCERT Eq. 13.14–13.15. Report a mistake