Find the energy equivalent of one atomic mass unit,first in $Joules$ and then in $MeV$. Using this,express the mass defect of $_{8}^{16} O$ in $MeV / c^{2}$.

(N/A) The mass of one atomic mass unit is $1 \, u = 1.6605 \times 10^{-27} \, kg$.
To convert this into energy units,we use Einstein's mass-energy equivalence relation $E = mc^2$:
$E = 1.6605 \times 10^{-27} \, kg \times (2.9979 \times 10^8 \, m/s)^2$
$E = 1.4924 \times 10^{-10} \, J$.
To convert this energy into $MeV$,we divide by $1.602 \times 10^{-13} \, J/MeV$:
$E = \frac{1.4924 \times 10^{-10}}{1.602 \times 10^{-13}} \, MeV \approx 931.5 \, MeV$.
Thus,$1 \, u = 931.5 \, MeV/c^2$.
For $_{8}^{16} O$,the mass defect $\Delta M = 0.13691 \, u$.
Converting this to $MeV/c^2$:
$\Delta M = 0.13691 \times 931.5 \, MeV/c^2 \approx 127.5 \, MeV/c^2$.