The atomic masses of two isotopes of an element are $34.98 \ u$ and $36.98 \ u$ and their relative abundances are $75.4 \%$ and $24.6 \%$ respectively. The average atomic mass of the element is: (in $u$)

Assertion: Isobars are the elements having same mass number but different atomic number.
Reason: Neutrons and protons are present inside the nucleus.

$A$ heavy nucleus at rest breaks into two fragments which fly off with velocities in the ratio $3: 1$. The ratio of radii of the fragments is

The nuclear radius of a hydrogen atom is approximately . . . . . . . (in $fm$)

An element consists of a mixture of three isotopes $A$, $B$, and $C$ of masses $m_1$, $m_2$, and $m_3$ respectively. If the relative abundances of the three isotopes $A$, $B$, and $C$ are in the ratio $2:3:5$, the average mass of the element is:

How many times is the density of the nucleus more than the density of water?