Question

Binding energy per nucleon for helium nucleus ${(}_2^{4}He)$ is 7.0 MeV. Find vallue of mass defect for helium nucleus.

Answer 1

$B.E./nucleon=7.0MeV$
Let, Mass defect $=\Delta m$
$\frac{B.E.}{nucleon}=\frac{\Delta m{c}^2}{Noofnucleus}$
$7.0=\frac{\Delta m\times (3\times {10}^8{)}^2}{4}$
$\Delta m=\frac{28}{9\times {10}^{16}}$
$=3.11\times {10}^{-16}kg$.