Part A

A glass bead charged to $+3\mathrm{.}2$ nC exerts an $6\mathrm{.}0{10}^{-4}N$ repulsive electric force on a plastic bead $2\mathrm{.}9$ cm away.

What is the charge on the plastic bead?

$+1\mathrm{.}8nC$

$+6\mathrm{.}0nC$

$+18nC$

$+600nC$