Write the unit of mass in nuclear physics and define it and it is equivalent to how many kilograms?

In the nuclear reaction $X(n, \alpha) _3^7Li$,what is $X$?

Which of the following statements is incorrect?

Four statements are given ($A$ is mass number) :
$A$. The volume of a nucleus is proportional to $A^{1/3}$.
$B$. The volume of a nucleus is proportional to $A$.
$C$. The difference in mass of an atom and its nucleus is called the mass defect.
$D$. The difference in mass of a nucleus and its constituents is called the mass defect.
Choose the correct answer from the options given below :

State the dimension of the nucleus from the Rutherford experiment.

The nuclei ${ }_{6} C^{13}$ and ${ }_{7} N^{14}$ can be described as