Energy of $1 \, g$ uranium is equal to

If $M_0$ is the mass of isotope ${ }_{5}^{12} B$,$M_p$ and $M_n$ are the masses of a proton and a neutron respectively,then the nuclear binding energy of the isotope is:

The mass defect in a particular reaction is $0.4 \,g$.
The amount of energy liberated is $n \times 10^7 \,kWh$,where $n =$ . . . . . . . (speed of light $= 3 \times 10^8 \,m/s$)

Given below are two statements. One is labelled as Assertion $(A)$ and the other is labelled as Reason $(R)$.
Assertion $(A) :$ The binding energy per nucleon is found to be practically independent of the atomic number $A$,for nuclei with mass numbers between $30$ and $170$.
Reason $(R) :$ Nuclear force is long range.
In the light of the above statements,choose the correct answer from the options given below $:$

Degenerate electron pressure will not be sufficient to prevent the core collapse of a white dwarf if its mass becomes $n$ times the solar mass. The value of $n$ is:

Write and explain Einstein's theory of special relativity in the context of mass-energy equivalence.