Physics - Electrostatics Question with Solution | TestHub

Work is equal to the potential energy of the system.

$U=4\frac{k\left(q\right)\left(-q\right)}{a}+2\frac{k\left(q\right)\left(q\right)}{a\sqrt{2}}$

$U=\frac{k{q}^2}{a}\left(-4+\sqrt{2}\right)$

$U=\frac{q^2}{\mathrm{\pi }{\epsilon }_{0}a}\left(-1+\frac{\sqrt{2}}{4}\right)=-\frac{0.65q^2}{\mathrm{\pi }{\epsilon }_{0}a}$