Four charges of $1\ \mu C, 2\ \mu C, 3\ \mu C,$ and $-6\ \mu C$ are placed at the corners of a square of side $1\ m$. The square lies in the $x-y$ plane with its center at the origin.

Ten charges are placed on the circumference of a circle of radius $R$ with constant angular separation between successive charges. Alternate charges $1, 3, 5, 7, 9$ have charge $(+q)$ each, while $2, 4, 6, 8, 10$ have charge $(-q)$ each. The potential $V$ and the electric field $E$ at the centre of the circle are respectively (Take $V = 0$ at infinity).

Two identical charged spheres suspended from a common point by two massless strings of lengths $l$ are initially at a distance $d$ $(d << l)$ apart because of their mutual repulsion. The charges begin to leak from both the spheres at a constant rate. As a result,the spheres approach each other with a velocity $v$. Then $v$ varies as a function of the distance $x$ between the spheres,as:

An infinite plane sheet of charge having uniform surface charge density $+\sigma_s \text{ C/m}^2$ is placed on the $x-y$ plane. Another infinitely long line charge having uniform linear charge density $+\lambda_e \text{ C/m}$ is placed at the $z=4 \text{ m}$ plane and is parallel to the $y$-axis. If the magnitude values satisfy $|\sigma_s| = 2|\lambda_e|$,then at the point $(0, 0, 2)$,the ratio of the magnitudes of the electric field values due to the sheet charge to that of the line charge is $\pi \sqrt{n} : 1$. The value of $n$ is:

$A$ particle of mass $2\,g$ and charge $1\,\mu C$ is released from a distance of $1\,m$ from a fixed charge of $1\,mC$. What will be the velocity of the particle at a distance of $10\,m$ from the fixed charge (in $m/s$)?

Four charges $2C, -3C, -4C$ and $5C$ are placed at the corners of a square. Which of the following statements is true for the point of intersection of the diagonals?