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Question: Answered & Verified by Expert
The radius of ${ }_{72} \mathrm{Te}^{125}$ nucleus is 6 fermi. The radius of ${ }_{13} \mathrm{Al}^{27}$ nucleus in meters is
PhysicsNuclear PhysicsTS EAMCETTS EAMCET 2013
Options:
  • A $3.6 \times 10^{-12} \mathrm{~m}$
  • B $3.6 \times 10^{-15} \mathrm{~m}$
  • C $7.2 \times 10^{-8} \mathrm{~m}$
  • D $7.2 \times 10^{-15} \mathrm{~m}$
Solution:
1108 Upvotes Verified Answer
The correct answer is: $3.6 \times 10^{-15} \mathrm{~m}$
The relation between radius $(R)$ and atomic number $(A)$ is
$\frac{R_1}{R_2}=\left(\frac{A_1}{A_2}\right)^{1 / 3}$
Given, $R_1=6$ fermi, $A_1=125, A_2=27$
$\begin{aligned}
\frac{6}{R_2} & =\left(\frac{125}{27}\right)^{1 / 3}=\frac{5}{3} \\
\Rightarrow \quad \quad \quad R_2 & =\frac{6 \times 3}{5}=\frac{18}{5}=3.6 \text { fermi } \\
& =3.6 \times 10^{-15} \mathrm{~m}
\end{aligned}$

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