$6 \mu \mathrm{C}$ charge is placed at the centre of a cube. What will be the electric flux at each face of the cube?

$$ \left[\text { Take, } \frac{1}{4 \pi \varepsilon_0}=9 \times 10^9 \mathrm{~N}-\mathrm{m}^2 \mathrm{C}^2\right] $$

There are two thin wire rings, each of radius $R$, whose axes coincide. The charges of the rings are $q$ and $-q$. The magnitude of potential difference between the centres of the rings separated by a distance $\sqrt{3} R$ is

Two charged particles of mass 1 g each are placed 1 m apart. If each of these possesses 1 femto coulomb of charge, then the dominant force of interaction between them is

Three charges are arranged on the vertices of a right angle triangle as shown in the figure. The magnitude of dipole moment of the combination in the unit of $\mathrm{C}-\mathrm{cm}$ is