$A$ charge of $0.8 \text{ C}$ is divided into two charges $Q_{1}$ and $Q_{2}$. These are kept at a separation of $30 \text{ cm}$. The force on $Q_{1}$ is maximum when

Two point charges $+3\,\mu C$ and $+8\,\mu C$ repel each other with a force of $40\,N$. If a charge of $-5\,\mu C$ is added to each of them,then the force between them will become....$N$

Two balls of same mass and carrying equal charge are hung from a fixed support of length $l$. At electrostatic equilibrium,assuming that the angle made by each thread is small,the separation $x$ between the balls is proportional to

Two point charges $+6 \mu C$ and $+10 \mu C$ kept at a certain distance repel each other with a force of $30 \ N$. If each charge is given an additional charge of $-8 \mu C$,the two charges:

If $\varepsilon_0$ and $\varepsilon$ represent the permittivity of free space and absolute permittivity of a medium,then the relative permittivity of the medium is:

The repulsive force between two particles of same mass and charge,separated by a certain distance,is equal to the weight of one of them. The distance between them is . . . . . . $\times 10^{-1} \ m$.
Mass of particle $= 1.66 \times 10^{-27} \ kg$
Charge of particle $= 1.6 \times 10^{-19} \ C$
$k = 9 \times 10^9 \ MKS, \ g = 10 \ ms^{-2}$