Nuclear force: potential energy of two nucleonsनाभिकीय बल: दो न्यूक्लिऑनों की स्थितिज ऊर्जाNuclear force: potential energy of two nucleons

NCERT Fig 13.2 · Class 12 Physics · Chapter 13 · interactive diagram

Parts and what they mean

• Potential energy U(r) (स्थितिज ऊर्जा U(r)) — A rough plot (as in NCERT): U falls to a minimum at r₀ and rises very steeply at smaller r. Force = −dU/dr.
• r₀ ≈ 0.8 fm (r₀ ≈ 0.8 fm) — Distance of minimum potential energy. Here the force is zero; two nucleons settle near this separation.
• Repulsive core (r < r₀) (प्रतिकर्षी क्रोड (r < r₀)) — Closer than about 0.8 fm the force is strongly repulsive — nucleons cannot be squeezed together. This keeps nuclear density constant.
• Attractive region (r > r₀) (आकर्षी क्षेत्र (r > r₀)) — Beyond 0.8 fm the force is attractive and very strong — much stronger than the Coulomb repulsion between protons.
• Short range (लघु परास) — The nuclear force falls rapidly to zero beyond a few femtometres. So a nucleon feels only its near neighbours (saturation).

Original diagram drawn by Simple Learning Hub, based on NCERT Fig 13.2. Report a mistake