Which of the following pairs is an isobar
$_1{H^1}$ and $_1{H^2}$
$_1{H^2}$ and $_1{H^3}$
$_6{C^{12}}$ and $_6{C^{13}}$
$_{15}{P^{30}}$ and $_{14}S{i^{30}}$
Write the definitions of isotopes, isobar and isotone.
If the nucleus ${}_{13}^{27}Al$ has a nuclear radius of about $3.6\,\, fm,$ then ${ }_{32}^{125} Te$ would have its radius approximately as .......$fm$
Write and explain the Einstein theory of special relativity.
The mass number of a nucleus is
The mass of a neutron is the same as that of