Two small spheres each having the charge $ + Q$ are suspended by insulating threads of length $L$ from a hook. This arrangement is taken in space where there is no gravitational effect, then the angle between the two suspensions and the tension in each will be
${180^o},\,\frac{1}{{4\pi {\varepsilon _0}}}\frac{{{Q^2}}}{{{{(2L)}^2}}}$
${90^o},\,\frac{1}{{4\pi {\varepsilon _0}}}\frac{{{Q^2}}}{{{L^2}}}$
${180^o},\,\frac{1}{{4\pi {\varepsilon _0}}}\frac{{{Q^2}}}{{2{L^2}}}$
${180^o},\,\frac{1}{{4\pi {\varepsilon _0}}}\frac{{{Q^2}}}{{{L^2}}}$
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
Three point charges are placed at the corners of an equilateral triangle. Assuming only electrostatic forces are acting
A paisa coin is made up of $\mathrm{Al - Mg}$ alloy and weighs $0.75\, g$. It has a square shape and its diagonal measures $17$ $\mathrm{mm}$. It is electrically neutral and contains equal amounts of positive and negative charges.
The unit of electric permittivity is
Two fixed charges $4\,Q$ (positive) and $Q$ (negative) are located at $A$ and $B$, the distance $AB$ being $3$ $m$.