What is the energy equivalent to one kilogram of mass?

The binding energy $(BE)$ per nucleon for an element is $7.14 \text{ MeV}$. If the total $BE$ of the element is $28.6 \text{ MeV}$, then the number of nucleons in the element is:

The energy equivalent to $1\,mg$ of matter in $MeV$ is

The energy equivalent of $1 \,g$ of substance is:

The binding energy per nucleon of $^{16}O$ is $7.97 \ \text{MeV}$ and that of $^{17}O$ is $7.75 \ \text{MeV}$. The energy (in $\text{MeV}$) required to remove a neutron from $^{17}O$ is:

The ratio of the orders of the spacings of nuclear energy levels and atomic energy levels is