Question

Electric charges of $+10\mu C,+5\mu C,-3\mu C$ and $+8\mu C$ are placed at the corners of a square of side $\sqrt{2}m$. The potential at the centre of the square is:

Answer 1

$V=\frac{K{q}_1}{r}+\frac{K{q}_2}{r}+\frac{K{q}_3}{r}+\frac{K{q}_4}{r}$
where r = 1 m
$=9\times {10}^9(10+5+8-3)\times {10}^{-6}$
$=1.8\times {10}^{5}V$