Question

The mass of helium atom is 4.0026 amu, while that of the neutron and proton are 1.0087 and 1.0078 amu respectively on the same scale. Hence, the nuclear binding energy per nucleon in the helium atom is about
A. 5 MeV
B. 12 MeV
C. 14 MeV
D. 7 MeV

Answer 1

Correct Answer - D
Mass defect of `._(2)He^(4), Delta m = [2(m_(p) + m_(n)) - m_(He)]`
`Deltam = [2(1.0087 + 1.0078) - 4.0026]`
`= 4.033 - 4.0026 rArr Delta m = 0.0304`
`:.` Binding energy per nucleon
`= (Deltam xx 931.5)/(4) = (0.0304 xx 931.5)/(4) = 7.01 MeV`