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

The radius of germanium $(Ge)$ nuclide is measured to be twice the radius of ${ }_4^9 Be$. The number of nucleons in $Ge$ will be

The mass number of a nucleus is

$\pi$ mesons can be

The nuclear reaction is represented by $X(n, \alpha) \to _3^7Li$. Which element is $X$?

The radius of a nucleus of mass number $64$ is $4.8 \text{ fermi}$. Then the mass number of another nucleus having radius of $4 \text{ fermi}$ is $\frac{1000}{x}$,where $x$ is . . . . . . .