In an alpha particle scattering experiment distance of closest approach for the α particle is 4.5 × 10^-14 m. If target nucleus has atomic number 80,…

In an alpha particle scattering experiment distance of closest approach for the $\displaystyle \alpha$ particle is $\displaystyle 4.5 \times 10^{-14} \mathrm{~m}$. If target nucleus has atomic number $\displaystyle 80$ , then maximum velocity of $\displaystyle \alpha$ - particle is $\displaystyle \_\_\_\_$ $\displaystyle \times 10^5 \mathrm{~m} / \mathrm{s}$ approximately. $\displaystyle \left(\frac{1}{4 \pi \epsilon_0}=9 \times 10^9\right.$ SI unit, mass of $\displaystyle \alpha$ particle $\displaystyle \left.=6.72 \times 10^{-27} \mathrm{~kg}\right)$