The measure of binding energy of a nucleus is the

During the emission of a positron from a nucleus, the mass number of the daughter element remains the same but the atomic number

The isotopic mass of ${}_{3}^{7}Li$ is $7.016005 \ u$ and those of the $H$ atom and neutron are respectively $1.007825 \ u$ and $1.008665 \ u$. Then,the binding energy of the ${}_{3}^{7}Li$ nucleus is: (in $MeV$)

Which one of the following nuclear reactions is not correct?

If two light nuclei are fused together in a nuclear fusion reaction,what happens to the average binding energy per nucleon?

Consider an $\alpha$-particle just in contact with a $_{92}U^{238}$ nucleus. Calculate the coulombic repulsion energy (i.e.,the height of the coulombic barrier between $U^{238}$ and $\alpha$-particle) assuming that the distance between them is equal to the sum of their radii.