In a hollow spherical shell, potential $(V)$ changes with respect to distance $(s)$ from centre as
A parallel plate condenser with plate area $A$ and separation $d$ is filled with two dielectric materials as shown in the figure. The dielectric constants are $K_1$ and $K_2$ respectively. The capacitance will be
Three charges $2q,\, - q,\, - q$ are located at the vertices of an equilateral triangle. At the centre of the triangle
A parallel plate capacitor has a uniform electric field $E$ in the space between the plates. If the distance between the plates is $d$ and area of each plate is $A$ , the energy stored in the capacitor is
A point charge $q$ is situated at a distance $d$ from one end of a thin non - conducting rod of length $L$ having a charge $Q$ (uniformly distributed along its length) as shown in fig.Then the magnitude of electric force between them is
Two opposite and equal charges $4 \times {10^{ - 8}}\, coulomb$ when placed $2 \times {10^{ - 2}}\,cm$ away, form a dipole. If this dipole is placed in an external electric field $4 \times 10^8\, newton / coulomb$ , the value of maximum torque and the work done in rotating it through $180^o$ will be