A hollow insulated conduction sphere is given a positive charge of $10\,\mu C$. What will be the electric field at the centre of the sphere if its radius is $2\,m$ ?................$\mu Cm^{-2}$
$0$
$5$
$20$
$8$
Capacity of an isolated sphere is increased $n$ times when it is enclosed by an earthed concentric sphere. The ratio of their radii is
The value of electric potential at any point due to any electric dipole is
Two point charges of $ + 2\,\mu C$ and $ + 6\,\mu C$ repel each other with a force of $12\, N$. If each is given an additional charge of $ - 4\,\mu C$, then force will become
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
Electric field at a place is $\overrightarrow E = {E_0}\widehat i\,\,V/m$. A particle of charge $+q_0$ moves from point $A$ to $B$ along a circular path find work done in this motion by electric field :-