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}$
In general, metallic ropes are suspended on the carriers which take inflammable material. The reason is
Force of attraction between two point charges $Q$ and $-Q$ separated by $d\,$ metre is ${F_e}$. When these charges are placed on two identical spheres of radius $R = 0.3\,d$ whose centres are $d\,$ metre apart, the force of attraction between them is
The law, governing the force between electric charges is known as
What is the net force on a $Cl^{-}$ placed at the centre of the bcc structure of $CsCl$
Two positive charges of $20$ $coulomb$ and $Q\;coulomb$ are situated at a distance of $60\,cm$. The neutral point between them is at a distance of $20\,cm$ from the $20\,coulomb$ charge. Charge $Q$ is.....$C$