Nuclear Force: Definition, Properties and Examples

The force that is known to bind the neutrons and protons together in an atom is known as the nuclear force. This force is the one responsible for holding the nucleus together. The protons in a nucleus have a positive electrical charge and except hydrogen, all atoms have a nucleus that contains more than one proton. So by rule, the charges that are alike in nature should repel each other but still, the nucleons in the nucleus of an atom stay together. Why is it so? This is due to the presence of nuclear force. 

Key Terms: Nuclear force, Nuclear reaction, Coulomb force, Nuclei, nucleus, nucleons, hydrogen, atom, electrical charge, proton

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Nuclear Force

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This force is stronger than the repulsive force or coulomb’s force which acts between the gravitational forces of masses. Thus it is able to overcome the resistance at a short-range and hold the nucleus together. The nuclear force which does not rely on electrical charge can exist in various forms, such as between the neutrons and protons, between protons and protons, or between the neutrons themselves. The amount of nuclear force that exists between these elements is also approximately the same. The nuclear force also cannot be represented in a simple mathematical form like Newton’s Law of Gravitation and Coulomb’s law. 

Nuclear Reaction

Nuclei Class 12 Important Notes PDF

Nuclei Class 12 Important Notes

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Properties of the Nuclear Force

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• The nuclear force has a repulsive core and yet it is attractive in nature. This force is responsible for preventing the collapsing of the nucleus, thus holding it together.
• The nuclear force is much stronger than the Coulomb force as it overpowers the repulsive forces between the alike protons inside the nucleus.
• Femtometre (fm) is the unit that is used to measure distances between any two nucleons. The distance between the particles in the nucleus is really small when it is 1 Fermi or 1 fm = 10^–15m. Here, in this range, the force is stronger than the Coulomb’s force which is repulsive in nature. 

Nuclear Force

• The nucleus force becomes almost non-existent if the distance between the particles in the nucleus is more than 2.5 Fermi.
• The nucleus force becomes repulsive when the distance between the particles is anything less than 0.7 Fermi. The size of the nucleus is decided by the repulsive property.
• Till the force allows, the nucleons can come closer to each other together. After a certain point, due to the repulsive nature of the force, the nucleons can’t come any closer together.

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Examples of Nuclear Force

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• The nuclear force is responsible for holding the nucleus together despite the presence of alike protons which is repulsive in nature.
• The nuclear force explains the fusion of Hydrogen into Helium at the core of the sun. 
• The nuclear force is also responsible for the destructive power of the nuclear weapons.When a nuclear weapon is detonated, there is a huge release of energy due the strength of nuclear forces.
• The phenomenons such as radioactive decay and radiocarbon dating also use this reaction of nuclear force.
• The nuclear force is used to generate heat to produce energy such as electricity through nuclear power plants.

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Things to Remember

• The force that is known to bind the neutrons and protons together in an atom is known as the nuclear force.
• This force is stronger than the repulsive force or coulomb’s force which acts between the gravitational forces of masses.
• The nuclear force has a repulsive core and yet it is attractive in nature. This force is responsible for preventing the collapsing of the nucleus, thus holding it together.
• The nucleus force becomes almost non-existent if the distance between the particles in the nucleus is more than 2.5 Fermi.
• The nuclear force is responsible for holding the nucleus together despite the presence of alike protons which is repulsive in nature.
• The nuclear force explains the fusion of Hydrogen into Helium at the core of the sun. 

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Previous Year Questions

1. Two nuclei have their mass numbers in the ratio...[KEAM 2008]
2. When the number of nucleons in a nuclues increases the binding….[NEET 2013]
3. For a radioactive material, half-life is 10 minutes….[NEET 2018]
4. A nucleus of uranium decays at rest into nuclei of thorium and helium...[NEET 2015]
5. Fusion reaction takes place at high temperature because…. [NEET 2011]
6. Which of the following process is allowed by momentum and energy conservation ?...[JEE Main 2020]
7. Which one of the following cannot be used as a moderator in a nuclear reactor?...[JKCET 2010]
8. An alpha particle of energy 5,MeV  is...[JEE Advance 1981]
9. In a radioactive decay chain, the initial nucleus is...[JEE Main 2019]