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Question
Calculate the Q-value of the fusion reaction 4He + 4He = 8Be. Is such a fusion energetically favourable? Atomic mass of 8Be is 8.0053 u and that of 4He is 4.0026 u.
(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.)
Solution
Given:-
Atomic mass of 8Be = 8.0053 u
Atomic mass of 4He = 4.0026 u
Required Q-value = `(2 xx 4.0026 - 8.0053) c^2`
`= 0.0001 xx 931 "MeV"`
`= 0.0001 xx 931 xx 10^6 "eV"`
= 93.1 KeV
No, such reaction is not favourable.
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