An alpha particle of energy 4 Mev is scattered by Gold foil (Z=79).  Calculate the Volume in which positive charge is likely to be concentrated

$$\begin{gathered} E=\frac{K.Z_{1}e.Z_{2}e}{r} \\ r=\frac{K.79e.2e}{E} \end{gathered}$$

$r=\frac{9\times {10}^9\times 79\times {1.6\times {10}^{-19}}^{ }x2\times 1.6x{10}^{-19}}{4\times {10}^6\times 1.6\times {10}^{-19}}$

$r=5.68\times {10}^{-14}m$

The formula for the volume of a sphere is V = 4/3 π r ³, where V = volume and r = radius. 

$V=\frac{4}{3}\times 3.14\times {\left(5.68\times {10}^{-14}\right)}^3$

$V=7.67\times {10}^{-40}$