n. 1 (context physics English) The force that acts between nucleons and binds protons and neutrons into atomic nucleus; the residual strong force 2 (context physics English) The strong interaction that binds quarks and gluons together to form nucleons; the colour force
The nuclear force (or nucleon–nucleon interaction or residual strong force) is the force between protons and neutrons, subatomic particles that are collectively called nucleons. The nuclear force is responsible for binding protons and neutrons into atomic nuclei. Neutrons and protons are affected by the nuclear force almost identically. Since protons have charge +1 e, they experience a strong electric field repulsion (following Coulomb's law) that tends to push them apart, but at short range the attractive nuclear force overcomes the repulsive electromagnetic force. The mass of a nucleus is less than the sum total of the individual masses of the protons and neutrons which form it. The difference in mass between bound and unbound nucleons is known as the mass defect. Energy is released when some large nuclei break apart, and it is this energy that is used in nuclear power and nuclear weapons.
The nuclear force is powerfully attractive between nucleons at distances of about 1 femtometer (fm, or 1.0 × 10 metres) between their centers, but rapidly decreases to insignificance at distances beyond about 2.5 fm. At distances less than 0.7 fm, the nuclear force becomes repulsive. This repulsive component is responsible for the physical size of nuclei, since the nucleons can come no closer than the force allows. By comparison, the size of an atom, measured in angstroms ( Å, or 1.0 × 10 m), is five orders of magnitude larger. The nuclear force is not simple, however, since it depends on the nucleon spins, has a tensor component, and may depend on the relative momentum of the nucleons.
A quantitative description of the nuclear force relies on partially empirical equations that model the internucleon potential energies, or potentials. (Generally, forces within a system of particles can be more simply modeled by describing the system's potential energy; the negative gradient of a potential is equal to the vector force.) The constants for the equations are phenomenological, that is, determined by fitting the equations to experimental data. The internucleon potentials attempt to describe the properties of nucleon–nucleon interaction. Once determined, any given potential can be used in, e.g., the Schrödinger equation to determine the quantum mechanical properties of the nucleon system.
Usage examples of "nuclear force".
But forces deep beneath the mainstream of their bureaucracy clandestinely constructed a nuclear force.
Because there is another force of nature: not gravity, not electricity, but the short-range nuclear force, which, like a set of hooks that engage only when protons and neutrons come very close together, thereby overcomes the electrical repulsion among the protons.
An invading 'slow' neutron passed close enough to a plutonium nucleus to fall under the Strong Nuclear Force that holds atomic nuclei together.
He noticed that the nuclear force-shield had vanished from about the man and admitted dryly to himself that his person no longer seemed formidable to strangers –.
He noticed that the nuclear force-shield had vanished from about the man and admitted dryly to himself that his person no longer seemed formidable to strangers--or even, for good or for evil, to his enemies.
He noticed that the nuclear force-shield had vanished from about the man and admitted dryly to himself that his person no longer seemed formidable to strangers -- or even, for good or for evil, to his enemies.
The success of the unification of the electromagnetic and weak nuclear forces led to a number of attempts to combine these two forces with the strong nuclear force into what is called a grand unified theory (or GUT).
Given what was happening in the Balkans, and the Falklands, and the recent ratcheting up of tension in Kashmir, and Chinese saber rattling in support of Pakistan, and the renewed spread of nuclear weapons, the US had no option but to make certain of the effectiveness of its own nuclear force.
The earliest one occurred when the strong nuclear force separated from the electromagnetic forces and the weak nuclear force.
Likewise the value of the strong nuclear force, which holds the nucleuses of atoms together even though the positively charged protons try to repel each other: if that force were only slightly weaker than it actually is, atoms would never form—.