\( \Rightarrow \,\,V\,\, = \,\,\frac{{V_{\max }^2\, \times \,\,m}}{{2\left( {\frac{q}{m}} \right)}}\,\, = \,\,\frac{{1.2\,\, \times \,\,{{10}^6} \times \,\,1.2\, \times \,\,{{10}^6}}}{{2\,\, \times \,\,(1.8\,\, \times \,\,{{10}^{11}})}}\,\, = \,\,4\)