The nuclear force between two nucleons is explained by

The ratio of the nuclear radii of the gold isotope ${}_{79}^{197}Au$ and the silver isotope ${}_{47}^{107}Ag$ is $ . . . . . . $.

Two deuterons are moving towards each other with the same speed. If the distance of closest approach is $2 \, fm$,what should be their initial kinetic energy in $MeV$?

Which stable nucleus has a radius that is half that of $Fe^{56}$?

If the nuclear force between two protons,two neutrons,and between a proton and a neutron is denoted by $F_{pp}$,$F_{nn}$,and $F_{pn}$ respectively,then:

Consider the following statements:
$I$. All isotopes of an element have the same number of neutrons.
$II$. Only one isotope of an element can be stable and non-radioactive.
$III$. All elements have isotopes.
$IV$. All isotopes of carbon can form chemical compounds with oxygen-$16$.
Choose the correct option regarding an isotope.