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Nuclear force
Intermediate
Strong, short-range and charge independent.
The strong force between nucleons is attractive at ~1 fm, very short range (about 2–3 fm), charge independent and repulsive at very short distances. It overcomes the electric repulsion between protons.
Stronger than electromagnetism by about 100 times at that range.
Residual of the quark–gluon force.
In more detail
The nuclear force binds protons and neutrons together in the nucleus. It is strong at short distances, about a femtometre, and charge independent, acting similarly on protons and neutrons.
Real-world uses
- Nuclear models use the nuclear force to explain binding energies.
- It explains why nuclei remain stable against electrical repulsion.
- Physicists use the strong nuclear force to explain why protons stay bound in a nucleus despite their electric repulsion.
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Frequently asked questions
Why is it not felt outside the nucleus?
Because it is very short-range, falling off rapidly beyond a few femtometres.
What carries the nuclear force?
Pions and other mesons are exchanged between nucleons, as in modern theory.
How does the strong force differ from electromagnetism?
It is much stronger but acts only over very short distances, about the size of a nucleus.
Related topics in Atomic & Nuclear Physics
Mass defect · Binding energy · Binding energy per nucleon · Radioactivity discovery · Alpha decay · Beta decay