A 1 MeV proton is sent against a gold leaf (Z = 79). Calculate the distance of closest approach for head on collision.

Question

$\begin{array}{1 1} (a)\;1.137 \times 10^{-13}\;m\\(b)\;2.137 \times 10^{-13}\;m\\ (c)\;3.137 \times 10^{-13}\;m\\ (d)\;4.137 \times 10^{-13}\;m\end{array} $