A charge $q$ is placed at the centre of the line joining two equal charges $Q$. The system of the three charges will be in equilibrium, if $q$ is equal to
$ - \frac{Q}{2}$
$ - \frac{Q}{4}$
$ + \frac{Q}{4}$
$ + \frac{Q}{2}$
A charge ${q_1}$ exerts some force on a second charge ${q_2}$. If third charge ${q_3}$ is brought near, the force of ${q_1}$ exerted on ${q_2}$
Two identical non-conducting thin hemispherical shells each of radius $R$ are brought in contact to make a complete sphere . If a total charge $Q$ is uniformly distributed on them, how much minimum force $F$ will be required to hold them together
A particle of mass $1 \,{mg}$ and charge $q$ is lying at the mid-point of two stationary particles kept at a distance $'2 \,{m}^{\prime}$ when each is carrying same charge $'q'.$ If the free charged particle is displaced from its equilibrium position through distance $'x'$ $(x\,< \,1\, {m})$. The particle executes $SHM.$ Its angular frequency of oscillation will be $....\,\times 10^{8}\, {rad} / {s}$ if ${q}^{2}=10\, {C}^{2}$
Why is an electric force conservative ?
Two small spherical balls each carrying a charge $Q = 10\,\mu C$ ($10$ micro-coulomb) are suspended by two insulating threads of equal lengths $1\,m$ each, from a point fixed in the ceiling. It is found that in equilibrium threads are separated by an angle ${60^o}$ between them, as shown in the figure. What is the tension in the threads......$N$ (Given: $\frac{1}{{(4\pi {\varepsilon _0})}} = 9 \times {10^9}\,Nm/{C^2}$)