Physics · nuclei · NEET
| Range | Short range, about 1 fm; nearly zero beyond 2-3 fm | Long range, follows inverse square law (1/r squared) |
| Strength (at ~1 fm) | Strongest force; larger than Coulomb at this range | About 230 N between two protons (weaker than nuclear) |
| Nature | Attractive at ~1 fm, repulsive below ~0.7 fm | Repulsive between two like charges (protons) |
| Charge dependence | Charge independent (same for p-p, p-n, n-n) | Acts only between charged particles |
| Acts on neutrons? | Yes, acts on protons and neutrons equally | No, neutrons are uncharged |
| Saturation | Saturates: each nucleon binds only close neighbours | No saturation; adds up over all proton pairs |
Yes. Between two protons about 1 fm apart, NCERT gives the Coulomb repulsion as roughly 230 N. The nuclear attraction at this distance is even larger (about 50 to 100 times stronger), which is why the nucleus stays bound instead of blowing apart. The nuclear force is the strongest of the basic forces at this tiny range.
The Coulomb force between protons is repulsive and does try to push them apart. But at the tiny nuclear distance (about 1 fm) the attractive nuclear force is much stronger, so it wins and holds the nucleus together. The Coulomb repulsion only becomes important for very heavy nuclei with many protons, which is why heavy nuclei become unstable.
The nuclear force is mainly attractive at normal nuclear distances (about 1 fm), which binds the nucleons. But at very short distances (below about 0.7 fm) it becomes strongly repulsive, which stops the nucleons from collapsing into each other. So it is attractive at 1 fm and repulsive when nucleons come too close.
No. The nuclear force is charge independent. It is the same between proton-proton, proton-neutron, and neutron-neutron pairs. The Coulomb force is the opposite: it acts only between charged particles, so it acts between two protons but not on neutrons at all.
The nuclear force acts only up to about a few femtometres and drops to nearly zero beyond about 2 to 3 fm, so each nucleon only feels its close neighbours (this is called saturation). The Coulomb force follows an inverse square law (1/r squared), so it never fully drops to zero and reaches across the whole nucleus and beyond.
The nuclear force. NCERT notes the Coulomb force between two protons in a nucleus is about 230 N while gravity is only about 1.9 x 10 to the power -34 N. The nuclear force is stronger than even the Coulomb force at this range, so gravity is completely negligible inside a nucleus.
The nuclear force is a very strong, short-range, charge-independent attractive force between nucleons. The Coulomb force is a long-range force between charges, and between two protons it is repulsive. Nuclear force dominates at about 1 fm; Coulomb dominates at large distances.
Yes. The nuclear force is charge independent, so it acts equally on protons and neutrons. The Coulomb force does not act on neutrons because neutrons have no charge.
In heavy nuclei there are many protons. The nuclear force saturates and only binds close neighbours, but the Coulomb repulsion adds up over all proton pairs and reaches across the whole nucleus. So the total Coulomb push grows faster and can make the nucleus unstable, leading to decay or fission.
At about 1 femtometre (1 fm = 10 to the power -15 m), the typical separation of nucleons inside a nucleus. NCERT gives the Coulomb force between two protons here as about 230 N, and the nuclear force is stronger still at this range.
No. It is attractive at about 1 fm, which binds nucleons, but it turns repulsive at very short distances (below about 0.7 fm). This repulsive core stops the nucleus from collapsing and keeps nuclear density nearly constant.
