Suppose three equal charges, each equal to +q, are placed at the vertices of an equilateral triangle of side 1, then the force exerted on a charge Q (with the same sign as q) placed at the centroid of the triangle is:
1
\(\rm -\frac{3qQ}{4\pi \epsilon_0l^2}\hat{r}\)
2
\(\rm \frac{3qQ}{4\pi \epsilon_0l^2}\hat{r}\)
3
\(\rm -\frac{6qQ}{4\pi \epsilon_0l^2}\hat{r}\)
4
0