# A point charge Q is placed at a point A origin (0,0). Calculate the electric field at b(x,y) in vector form .

$\vec{E}$ = (KQ/r2)$\hat{r}$ = (KQ/r3)$\vec{r}$
$\vec{r}$ = $\vec{r_{b}}$ – $\vec{r_{a}}$ = x$\hat{i}$ + y$\hat{j}$
Then r = $\sqrt{x^{2} + y^{2}}$
Then $\vec{E}$ = KQ(x$\hat{i}$ + y$\hat{j}$)/(x2 + y2)3/2