Question $11$

$5$ Points

Four identical point charges $(+4\mathrm{.}0$ mC$)$ are placed at the corners of a square which has $20-$cm sides. How much work is required to assemble this charge arrangement starting with each of the charges a very large distance from any of the other charges?

$+2\mathrm{.}9$ J

$+3\mathrm{.}9$ J

$+2\mathrm{.}2$ J

$+4\mathrm{.}3$ J

$+1\mathrm{.}9$ J