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Question
In a typical nuclear reaction, e.g.
`"_1^2H+"_1^2H ->"_2^3He + n + 3.27 \text { MeV },`
although number of nucleons is conserved, yet energy is released. How? Explain.
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Solution
In a nuclear reaction, the sum of the masses of the target nucleus `("_1^2H)`and the bombarding particle `("_1^2H)` may be greater or less than the sum of the masses of the product nucleus `("_1^3He)` and the outgoing particle `("_0^1n).` So from the law of conservation of mass-energy some energy (3.27 MeV) is evolved or involved in a nuclear reaction. This energy is called Q-value of the nuclear reaction.
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(Use Mass of proton mp = 1.007276 u, Mass of `""_1^1"H"` atom = 1.007825 u, Mass of neutron mn = 1.008665 u, Mass of electron = 0.0005486 u ≈ 511 keV/c2,1 u = 931 MeV/c2.)
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(Use Mass of proton mp = 1.007276 u, Mass of `""_1^1"H"` atom = 1.007825 u, Mass of neutron mn = 1.008665 u, Mass of electron = 0.0005486 u ≈ 511 keV/c2,1 u = 931 MeV/c2.)
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