# Tag Info

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What is meant by mass defect of a single neutron or a single proton? The reduction in its mass. The mass defect of a nucleus represents the mass of the energy binding the nucleus, and is the difference between the mass of a nucleus and the sum of the masses of the nucleons of which it is composed. It isn't quite that, in that binding energy is ...

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Considering the neutron/proton as a single atom, the mass defect is by definition zero, as there are no binding energies, which tie your particle to something else.

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Note that the combined rest masses of the quarks (~10 MeV/$c^2$) account for about 1% of the proton and neutron mass (~938 MeV/$c^2$), the main contribution to the mass are the gluons from the Strong Force. Since the composition of the proton and neutron are different, so is the force that binds them.

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When matter and antimatter combine they produce two gamma rays with energy equal to their mass.

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When you talk about increasing the mass of an electron you are presumably mean the idea of relativistic mass. However you should note that relativistic mass is a generally misleading concept and not used these days. If you're interested there is a good discussion on this in the answers to Does the (relativistic) mass change? Why?. The relativistic mass idea ...

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The answer is simply yes. As long as conservation laws are satisfied. Nothing is to be regarded as $0$ energy, $0$ mass, $0$ charge, and so on. Keep in mind that mass is a positive form of energy, while interacting energy (like gravity) is a negative form of energy. You can see the link for more details ...

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Can matter be created in a pure vacuum (with no energy)? It's a subtle question. Firstly, how do we know whether there is energy? But even if there were energy if it was a minimum of energy then you wouldn't be able to use it to make things, and the energy minimum would be considered a good vacuum. But can you make particles? If they just appeared ...

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Both in classical as in quantum mechanics, energy is the conserved charge (in the sense of the Noether's theorem) of a system (Hamiltonian) which is invariant up to time translations. This is the most general definition of energy. It does not depend on the nature of the system (being either matter or radiation). Also note that at least in special ...

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