Answer: (4) 27.9 MeV
Consider an alpha particle (24He),
Number of p[rotons = 2
Number of Neutrons = 2
The mass defect formula
ΔM = 2mp + 2mn – mHe
ΔM = 2 ✕ (1.00783) + 2 ✕ (1.00867) – 4.00300
ΔM = 2.0157 + 2.0173 – 4.00300
∴ ΔM = 0.03 amu
Formula to calculate bonding energy of the alpha particle
B.E = ΔMc2
1 amu c2 = 931.5MeV
B.E = 0.03 ✕ 931.5
B.E = 27.9 MeV