Question

The ratio of the nuclear radius, of an atom with mass number $A$ and ${}_2^{4}He$ is ${\left(14\right)}^{\frac{1}{3}}$ . What is the value of $A$ ?

Answer 1

Answer: 56

From the relation $r\propto A^{1/3}$ ,
we have, $\frac{r_2}{r_1}={\left(\frac{A_2}{A_1}\right)}^{1/3}$
or ${\left(\frac{A_2}{4}\right)}^{1/3}={\left(14\right)}^{1/3}$
Therefore, $A_2=56$