Question

A one-dimensional row of positive ions, each with charge+Q and separated from its neighbors by a distance d, occupies theright-hand half of the x axis. That is, there is a +Q charge at , x= 0, x = +d, x = +2d and so on out to infinity.

Part a)
If an electron is placed at the position x = -d , determine F , themagnitude of force that this row of charges exerts on theelectron.

which one is it from the ff. choices?

F = (pi*e*Q^2) / (24*epsilon_0*d)

or

F = (pi*e*Q^2) / (24*epsilon_0*d^2)

or

F = (pi*e*Q) / (24*epsilon_0*d)

or

F = (pi*e*Q) / (24*epsilon_0*d^2)
Part b)
If the electron is instead placed at x = -3d , what is the value ofF?