In the nuclear reaction: $X(n, \alpha) {_3Li^7}$,the term $X$ will be

$A$ reaction between a proton and $_8^{18}O$ that produces $_9^{18}F$ must also liberate:

The radius of ${ }_{29} Cu^{64}$ nucleus in Fermi is (given $R_{0}=1.2 \times 10^{-15} \ m$)

An unstable heavy nucleus at rest breaks into two nuclei which move away with velocities in the ratio of $8:27$. The ratio of the radii of the nuclei (assumed to be spherical) is

The force between a proton and a proton in a nucleus is .......

The radius of a nucleus with atomic number $Z = 50$ is $9 \times 10^{-13} \ m$. The electric potential at its surface is: