Two equal positive charges are kept at points $A$ and $B$. The electric potential, while moving from $A$ to $B$ along straight line,

Two charges $+q$ and $-q$ are placed at a distance $b$ apart as shown in the figure below.

The electric field at a point $P$ on the perpendicular bisector as shown as :

$5$ charges each of magnitude ${10}^{-5} \mathrm{C}$ and mass $1 \mathrm{kg}$ are placed (fixed) symmetrically about a movable central charges of magnitude $5\times {10}^{-5} \mathrm{C}$ and mass $0.5 \mathrm{kg}$ as shown. The charges at $P_1$ is removed. The acceleration of the central charge is:

$\left[\mathrm{Given} O{P}_1=O{P}_2=O{P}_3=O{P}_4=O{P}_5=1 \mathrm{m}; \frac{1}{4\mathrm{\pi }{\epsilon }_0}=9\times {10}^9 \mathrm{in} \mathrm{Sl} \mathrm{units}\right]$

Two charges $+Q$ and $-2Q$ are located at points $A$ and $B$ on a horizontal line as shown below.

The electric field is zero at a point which is located at a finite distance