Chapter 5.1, Problem 5CP

Arrange the following pairs of charged particles in order of increasing electrostatic potential energy.

$\begin{array}{l}\begin{array}{l}\text{a)}\hfill \\ \text{i < ii < iii < iv}\hfill \\ \text{b)}\hfill \\ \text{iv < iii < ii < i}\hfill \\ \text{c)}\hfill \\ \text{I = iii < ii < iv}\hfill \\ \text{d)}\hfill \\ \text{ii < i = iii < iv}\hfill \\ \text{e)}\hfill \end{array}\\ \text{iv < i = ii < iii}\end{array}$