Two spherical nuclei have mass numbers $216$ and $64$ with their radii $R_1$ and $R_2$ respectively. The ratio,$\frac{R_1}{R_2}$ is equal to

Which of the following pairs is called isotones?

Highly energetic electrons are bombarded on a target of an element containing $30$ neutrons. The ratio of the radius of the nucleus to that of a Helium nucleus is $14^{1/3}$. The atomic number of the nucleus will be

Given below are two statements $:$ one is labelled as Assertion $(A)$ and the other is labelled as Reason $(R)$.
Assertion $(A) :$ The density of the copper $\left({ }_{29}^{64} Cu \right)$ nucleus is greater than that of the carbon $\left({ }_6^{12} C \right)$ nucleus.
Reason $(R) :$ The nucleus of mass number $A$ has a radius proportional to $A^{1/3}$.
In the light of the above statements,choose the most appropriate answer from the options given below.

The volume of a nucleus is directly proportional to

If the radius of the $^{27}_{13}Al$ nucleus is taken to be $R_{Al}$,then the radius of the $^{125}_{53}Te$ nucleus is nearly