Physics

Problem

A charge

+q

is fixed at each of the points

x = x_0, x = 3x_0, x = 5x_0, \dots, x = \infty

on the

x

axis, and a charge

-q

is fixed at each of the points

x = 2x_0, x = 4x_0, x = 6x_0, \dots, x = \infty

. Here

x_0

is a positive constant. Take the electric potential at a point due to a charge

Q

at a distance

r

from it to be

Q/(4\pi\epsilon_0 r)

. Then, the potential at the origin due to the above system of charges is a. 0 b.

\frac{q}{8\pi\epsilon_0 x_0 \ln 2}

\infty

\frac{q \ln 2}{4\pi\epsilon_0 x_0}