Question

The ratio of the nuclear radii of elements with mass numbers $216$ and $125$ is

• A. $216 : 125$
• B. $\sqrt {216} : \sqrt {125}$
• C. $6 : 5$
• D. none of these

Answer 1

Answer: (C)

$6 : 5$

Answer 2

Nuclear radius is proportional to $A^{1 / 3}$,
where $A$ is the mass number of nucleus.
$R=R_{0} A^{1 / 3}$
where $R_{0}=1.2\, fm$
$\frac{R_{1}}{R_{2}}=\frac{R_{0}(216)^{1 / 3}}{R_{0}(125)^{1 / 3}}=\frac{6}{5}$