The volume of a nucleus is proportional to ........ (where,$A$ is the mass number of the nucleus).

The density of a nucleus is $\qquad$ the atomic mass number $A$.

Which of the following is most unstable?

Consider the following two statements, $A$ and $B$ and identify the correct answer given below:
$A$. Nuclear density is same for all nuclei.
$B$. Radius of the nucleus $R$ and its mass number $A$ are related as $\sqrt{A} \propto R^{1 / 6}$.

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

It is now believed that protons and neutrons (which constitute nuclei of ordinary matter) are themselves built out of more elementary units called quarks. $A$ proton and a neutron consist of three quarks each. Two types of quarks,the so-called 'up' quark (denoted by $u$) of charge $+(2/3)e$,and the 'down' quark (denoted by $d$) of charge $-(1/3)e$ together with electrons build up ordinary matter. Suggest a possible quark composition of a proton and neutron.