The radius of the nucleus of an atom whose mass number is $125$ is:

Two nuclei of $Cu^{64}$ are in contact with their surfaces touching. What is the electrostatic potential energy between them in $MeV$?

Which is the correct unit for measuring nuclear radii?

If the radii of ${}_{13}^{27}Al$ and ${}_{30}^{64}Zn$ nuclei are $R_{1}$ and $R_{2}$ respectively,then $\frac{R_{1}}{R_{2}} = $

The nuclei ${ }_{6} C^{13}$ and ${ }_{7} N^{14}$ can be described as

Given below are two statements $:$ one is labelled as Assertion $(A)$ and other is labelled as Reason $(R).$
Assertion $(A) :$ Neutrons penetrate matter more readily as compared to protons.
Reason $(R) :$ Neutrons are slightly more massive than protons.