A nucleus with atomic mass number ' $A$ ' produces another nucleus by loosing 2 alpha particles. The volume…

A nucleus with atomic mass number ' $A$ ' produces another nucleus by loosing 2 alpha particles. The volume of the new nucleus is 60 times that of the alpha particle. The atomic mass number A of the original nucleus is
  1. $228$
  2. $238$
  3. $248$
  4. $244$

Solution

${ }_Z^A X \xrightarrow{-\infty-\text { particle }}{ }_{\mathrm{Z}-2}^{\mathrm{A}-4} \mathrm{Y} \xrightarrow{-\infty-\text { particle }}{ }_{\mathrm{Z}-4}^{\mathrm{A}-8} \mathrm{R}$ Volume of $\mathrm{R}=60\left(\right.$ Volume of $\left.{ }_2^4 \mathrm{He}\right)$ $\Rightarrow \frac{4}{3} \pi r_1^3=60 \times \frac{4}{3} \pi r_2^3 \Rightarrow\left(R_0 A_1^{\frac{1}{3}}\right)^3=60\left(R_0 A_2^{\frac{1}{3}}\right)^3$ $\Rightarrow(\mathrm{A}-8)=60 \times 4 \quad \therefore \quad A=248$

Asked in: AP EAMCET 2024 (20 May Shift 1)

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