\(n \frac{4}{3} \pi r ^{3}=\frac{4}{3} \pi\left( r ^{\prime}\right)^{3}\)
\(\Rightarrow r ^{\prime}= n ^{\frac{1}{3} r }\)
\(V =\frac{ kq }{ r } \propto \frac{ n }{ n ^{1 / 3}} \propto n ^{2 / 3} \propto 27^{2 / 3} \Rightarrow v ^{\prime}=9 V =9 \times 22=198\)
($e=1.6 \times10^{-1}9\; C$,$m_e=9.11 \times 10^{-3}\;kg$)