The electric field lines on the left have twice the separation on those on the right as shown in figure. If the magnitude of the field at $$A$$ is $$40 \mathrm{~Vm}^{-1}$$, what is the force on $$20 \mu \mathrm{C}$$ charge kept at $$B$$ ?
An infinitely long thin straight wire has uniform charge density of $$\frac{1}{4} \times 10^{-2} \mathrm{~cm}^{-1}$$. What is the magnitude of electric field at a distance $$20 \mathrm{~cm}$$ from the axis of the wire?
A dipole moment $$p$$ and moment of inertia $$I$$ is placed in a uniform electric field $$\mathbf{E}$$. If it is displaced slightly from its stable equilibrium position, the period of oscillation of dipole is
The difference between equivalent capacitances of two identical capacitors connected in parallel to that in series is $$6 \mu \mathrm{F}$$. The value of capacitance of each capacitor is