Two charges placed in air repel each other by a force of ${10^{ - 4}}\,N$. When oil is introduced between the charges, the force becomes $2.5 \times {10^{ - 5}}\,N$. The dielectric constant of oil is

Two identical pendulum $A$ and $B$ are suspended from the same point. The bobs are given positive charges, with $A$ having more charge than $B$ . They diverge and reach at equilibrium, with $A$ and $B$ making angles $\theta _1$ and $\theta _2$ with the vertical respectively, Then

Why Coulomb’s law is associated with Newton’s $3^{rd}$ law ?

A charge of $Q$ coulomb is placed on a solid piece of metal of irregular shape. The charge will distribute itself

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

The electrostatic force of interaction between an uniformly charged rod having total charge $Q$ and length $L$ and a point charge $q$ as shown in figure is