Question

The mass of proton is $1.0073u$ and that of neutron is $1.0087u$ (u = atomic mass unit) The binding energy of ${}_{2}^{4}$ He, if mass of ${}_{2}^{4}$he is $4.0015$u

• A. $0.0305erg$
• B. $0.0305J$
• C. $28.4MeV$
• D. $0.061u$

Answer 1

Answer: (C)

$28.4MeV$

Answer 2

: $\Delta m = 2m_{p} + 2m_{n} - m(_{2}^{4}He)$

$= 2 \times 1.0073 + 2 \times 1.0087 - 4.0015 = 0.0305u$

Binding energy

$= 0.0305 \times 931 ⥂ MeV = 28.4MeV$