An electron and a positron annihilate each other to produce two $\gamma$-ray photons of equal energy. The minimum energy of each photon is .....

The masses of neutron, proton and deuteron in amu are $1.00893$, $1.00813$ and $2.01473$, respectively. The packing fraction of the deuteron in amu is

If $M_{O}$ is the mass of an oxygen isotope ${ }_{8}^{17}O$, $M_{p}$ and $M_{n}$ are the masses of a proton and a neutron, respectively, the nuclear binding energy of the isotope is

Binding energy of a certain nucleus is $18 \times 10^8 \ J$. How much is the difference between the total mass of all the nucleons and the nuclear mass of the given nucleus (in $\mu g$)?

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

For a nucleus ${ }_Z^A X$ having mass number $A$ and atomic number $Z$:
$A.$ The surface energy per nucleon $(b_s) = a_1 A^{2/3}$
$B.$ The Coulomb contribution to the binding energy $b_c = -a_2 \frac{Z(Z-1)}{A^{4/3}}$
$C.$ The volume energy $b_v = a_3 A$
$D.$ Decrease in the binding energy is proportional to surface area.
$E.$ While estimating the surface energy,it is assumed that each nucleon interacts with $12$ nucleons,($a_1, a_2$ and $a_3$ are constants)
Choose the most appropriate answer from the options given below: