The composition of an $\alpha$-particle can be expressed as:

If the radius of $_{13}^{27}Al$ is $3.6 \ fm$,then the radius of the $_{52}^{125}Te$ nucleus will be ........ $fm$.

Consider the following statements:
$I$. All isotopes of an element have the same number of neutrons.
$II$. Only one isotope of an element can be stable and non-radioactive.
$III$. All elements have isotopes.
$IV$. All isotopes of carbon can form chemical compounds with oxygen-$16$.
Choose the correct option regarding an isotope.

What is the ratio of the radii of the nuclei $_{13}^{27}Al$ and $_{52}^{125}Te$?

Consider the following nuclear reactions:
$I$. ${ }_{7}^{14} N +{ }_{2}^{4} He \longrightarrow{ }_{8}^{17} O + X$
$II$. ${ }_{4}^{9} Be +{ }_{2}^{4} He \longrightarrow{ }_{6}^{12} C + Y$
Then,

Assume that a neutron breaks into a proton and an electron. The energy released during this process is: ............ $MeV$ (mass of neutron $= 1.6725 \times 10^{-27} \ kg$,mass of proton $= 1.6725 \times 10^{-27} \ kg$,mass of electron $= 9 \times 10^{-31} \ kg$).