Q. If $r_{1}$ and $r_{2}$are the radii of the atomic nuclei of mass numbers 64 and 125 respectively, then the ratio ($r_{1}/r_{2}$) is
A) $\frac{64}{125}$
B) $\sqrt{\frac{64}{125}}$
C) $\frac{5}{4}$
D) $\frac{4}{5}$
Explanation
(d) $\ r = r_{0}(A)^{1/3}$
$\therefore\ \ \ \ \ \ \ \ \frac{r_{1}}{r_{2}} = \left( \frac{A_{1}}{A_{2}} \right)^{1/3} = \left( \frac{64}{125} \right)^{1/3}$
$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ = \left\lbrack \left( \frac{4}{5} \right)^{3} \right\rbrack^{1/3} = \frac{4}{5}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.