There are two charges $+1$ microcoulombs and $+5$ microcoulombs. The ratio of the forces acting on them will be

Point charge $q$ moves from point $P$ to point $S$ along the path $PQRS$ (figure shown) in a uniform electric field $E$ pointing coparallel to the positive direction of the $X - $axis. The coordinates of the points $P,\,Q,\,R$ and $S$ are $(a,\,b,\,0),\;(2a,\,0,\,0),\;(a,\, - b,\,0)$ and $(0,\,0,\,0)$ respectively. The work done by the field in the above process is given by the expression

$5$ charges each of magnitude $10^{-5} \,C$ and mass $1 \,kg$ are placed (fixed) symmetrically about a movable central charge of magnitude $5 \times 10^{-5} \,C$ and mass $0.5 \,kg$ as shown in the figure given below. The charge at $P_1$ is removed. The acceleration of the central charge is [Given, $\left.O P_1=O P_2=O P_3=O P_4=O P_5=1 m , \frac{1}{4 \pi \varepsilon_0}=9 \times 10^9\right]$

Three points charges are placed at the corners of an equilateral triangle of side $L$ as shown in the figure.

Three charges are placed at the vertices of an equilateral triangle of side ‘$a$’ as shown in the following figure. The force experienced by the charge placed at the vertex $A$ in a direction normal to $BC$ is

If two charges of $1$ coulomb each are placed $1 \,km$ apart, then the force between them will be ........... $N$