The ratio of mass densities of nuclei of $^{40}Ca$ and $^{16}O$ is close to

Antiparticle of electron is

Mark the correct statement

Which of the following pairs is an isobar

For effective nuclear forces, the distance should be

The nuclear radius is given by $R=r_0 A^{1 / 3}$, where $r_0$ is constant and $A$ is the atomic mass number. Then, the nuclear mass density of $U^{238}$ is