The mass of a proton is $1.0073 \; u$ and that of a neutron is $1.0087 \; u$ ($u =$ atomic mass unit). The binding energy of ${ }_2^4 \text{He}$ is (Given: helium nucleus mass $\approx 4.0015 \; u$):

Calculate the energy equivalent of $1 \ g$ of substance.

In the nuclear reaction $_1^2H + _1^3H \to _2^4He + _0^1n$, if the binding energies of $_1^2H$, $_1^3H$, and $_2^4He$ are respectively $a$, $b$, and $c$ (in $MeV$), then the energy (in $MeV$) released in this reaction is:

Deuteron is a bound state of a neutron and a proton with a binding energy $B = 2.2 \, MeV$. $A$ $\gamma$-ray of energy $E$ is aimed at a deuteron nucleus to try to break it into a (neutron + proton) such that the $n$ and $p$ move in the direction of the incident $\gamma$-ray. If $E = B$,show that this cannot happen. Hence,calculate how much bigger than $B$ must $E$ be for such a process to happen.

$\gamma$-rays radiation can be used to create an electron-positron pair. In this process of pair production,$\gamma$-rays energy cannot be less than ....... $MeV$.

One atomic mass unit is equivalent to .............. $MeV$ energy.