Physics - Modern Physics Question with Solution | TestHub

Given here,  $m_{\mathrm{He}}=4.0015 \mathrm{u}$, $m_p=1.0073 \mathrm{u}$ and $m_n=1.0087 \mathrm{u}$.

Mass defect

 $$\begin{gathered} ∆m = 2m_p+2m_n-m_{\mathrm{He}} \\ =2\times 1.0073+2\times 1.0087-4.0015 \\ =0.0305 \mathrm{u} \end{gathered}$$

Binding energy 

$$\begin{gathered} E = ∆m\times 931 \mathrm{MeV} \\ =0.0305\times 931 \\ =28.4 \mathrm{MeV} \end{gathered}$$