- #1

timn

- 19

- 0

## Homework Statement

Calculate the work required to bring a positive ion of charge e from infinity to a distance s from another ion of the same charge.

e<--s--->e

## Homework Equations

[tex] E = C \frac{q_1 q_2}{r^2} [/tex]

## The Attempt at a Solution

Integrate the energy from infinity to s besides the fixed ion, which resides on origin.

[tex]

W = \int_s^\infty E dr

= C\frac{e^2}{s}

[/tex]

The answer should not have Coloumb's constant in there. What did I miss?

(Note that this only is a part of problem 1.8 from Purcell's Electricity and Magnetism. I might have missed something in my simplification.)