Weak nuclear force always operates between

In the atomic scale,the weakest force in nature is

Particles and their anti-particles have

The charge density $P$ in a nucleus varies with distance $r$ from the centre of the nucleus according to the curve in the figure. Which of the following graphs correctly represents this variation?

If the radius of a nucleus with mass number $125$ is $1.5 \text{ fermi}$, then the radius of a nucleus with mass number $64$ is: (in $\text{ fermi}$)

The radius of a Germanium $(Ge)$ nucleus is twice the radius of a $^9_4Be$ nucleus. The number of nucleons in $Ge$ is ......