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

$1 \text{ a.m.u.}$ is equivalent to

Derive the formula for the binding energy of a nucleus by explaining the mass defect of the nucleus and write the formula for the binding energy per nucleon.

The mass of a proton is $1.0073 \, u$ and that of a neutron is $1.0087 \, u$. The binding energy of $_2He^4$ is .... ($u = \text{atomic mass unit}$,mass of helium nucleus = $4.0015 \, u$)

The sun radiates energy in all directions. The average radiation received on the earth's surface from the sun is $1.4 \; kW/m^2$. The average earth-sun distance is $1.5 \times 10^{11} \; m$. Calculate the mass lost by the sun per day $(1 \; \text{day} = 86400 \; s)$.

Nucleus $A$ having $Z=17$ and an equal number of protons and neutrons has $1.2 \, MeV$ binding energy per nucleon. Another nucleus $B$ of $Z=12$ has a total of $26$ nucleons and $1.8 \, MeV$ binding energy per nucleon. The difference in binding energy of $B$ and $A$ will be $........... \, MeV$.