An infinite number of charges each equal to 'q' are placed along the X-axis at $x=1$, $x=2$, $x=4$, $x=8$ ..... The potential at the point x = 0 due to this set of charges is

We know V due to charge q $=r.kQ $

V is a scalar quantity

total potential at 0 is just sum of all charges.

$∴V=1kq +2kq +4kq +−−−−$

$=kq(1−21 1 )$ (sum of infinite $G.P=1−ra )$

$V=4πε_{0}q 2$

$∴V=4πε_{0}2q $