Q162 / 180 · KCET 2024 · Physics
The ratio of volume of $\mathrm{Al}^{27}$ nucleus to its surfactarea is (Given, $R_0=1.2 \times 10^{-15} \mathrm{~m}$ )
- A$2.1 \times 10^{-15} \mathrm{~m}$
- B$1.3 \times 10^{-15} \mathrm{~m}$
- C$0.22 \times 10^{-15} \mathrm{~m}$
- Correct answerD$1.2 \times 10^{-15} \mathrm{~m}$
Solution
$\frac{\text { Volume of } \mathrm{Al}^{27} \text { nucleus }}{\text { Surface area }}=\frac{\frac{4}{3} \pi R^3}{4 \pi R^2}=\frac{R}{3}$
$=\frac{1}{3}\left(R_0 A^{\frac{1}{3}}\right) \quad\left[\because R=R_0 A^{\frac{1}{3}}\right]$
$=\frac{1}{3} \times 1.2 \times 10^{-15}(27)^{\frac{1}{3}}$
$=1.2 \times 10^{-15} \mathrm{~m}$
Hence, the correct answer is option: 'D'.