A small spherically symmetric charge $q$ is placed at one vertex of a cube as shown. The flux through the faces $ABCD$ and $HGEF$ are, respectively,

Charges $Q, 2Q$ and $4Q$ are uniformly distributed in three dielectric solid spheres $1, 2$ and $3$ of radii $\frac{R}{2}, R$ and $2R$ respectively, as shown in the figure. If magnitudes of the electric fields at point P at a distance R from the centre of spheres $1, 2$ and $3$ are $E_1\mathit{,} E_2$ and $E_3$ respectively, then 

In the following figure, if magnitude of force between $B$ and $C$ is $F$, then magnitude of force between $A$ and $B$ is $nF.$ The value of $n$ is _____.

The electric field at point $O$, due to the segment of a ring, whose linear charge density is $8 \mathrm{C} {\mathrm{cm}}^{–1}$ is $n\times {10}^{13} \mathrm{V} {\mathrm{m}}^{–1}.$ The value of $n$ is _____.

The magnitude of dipole moment of the following system is $\sqrt{n}qa$. The value of $n$ is _____.