Answer
a) $-3.46kQ/l$ at top
b) $-6.85kQ/l$ on left
c) $-5.15kQ/l$ on right
Work Step by Step
Electric potential is a scalar quantity and can be calculated by, $k\frac{Q}{r}$
a) $k(\frac{-2Q}{l}+\frac{2Q}{l}+\frac{-6Q}{\sqrt{3}l})=-3.46kQ/l$ at top
b) $k(\frac{-2Q}{l}+\frac{2Q}{\sqrt{3}l}+\frac{-6Q}{l})=-6.85kQ/l$ on left
c) $k(\frac{-2Q}{\sqrt{3}l}+\frac{2Q}{l}+\frac{-6Q}{l})=-5.15kQ/l$ on right
