\(\frac{k q}{1}-\frac{k q}{2}+\frac{k q}{4}-\frac{k q}{8}+\ldots \ldots\)

\(k q\left[1-\frac{1}{2}+\frac{1}{4}-\frac{1}{8}+\ldots \ldots\right]\)

\(\frac{k q \cdot 1}{1-\left(\frac{-1}{2}\right)}=V\)

\(V=\frac{2 k q}{3}\)