The masses of neutron and proton are 1.0087 a.m.u. and 1.0073 a.m.u. respectively. If the neutrons and protons combine to form a helium nucleus (alpha particles) of mass 4.0015 a.m.u. The binding energy of the helium nucleus will be (1 a.m.u.= 931 MeV)

Options

A. 28.4 MeV
B. 20.8 MeV
C. 27.3 MeV
D. 14.2 MeV

Answer

A

Explanation

Mass defect `(Delta m)= [2(M_(n) + M_(p))- m_(He)] = [2(1.0087 + 1.0073)- 4.0015]`
= 0.0305u
Binding energy `= (Delta m xx 931.5) MeV= 28.4MeV`