Two charged spherical conductors of radii $R_1$ and $R_2$ are connected by a wire. The ratio of surface charge densities of the spheres $\sigma _1/\sigma _2$ will be
$\frac{{{R_1}}}{{{R_2}}}$
$\frac{{{R_2}}}{{{R_1}}}$
$\sqrt {\left( {\frac{{{R_1}}}{{{R_2}}}} \right)} $
$\frac{{R_1^2}}{{R_2^2}}$
Find capacitance across $AB$
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 electric potential $(V)$ as a function of distance $(x)$ [in meters] is given by $V = (5x^2 + 10 x -9)\, Volt$. The value of electric field at $x = 1\, m$ would be......$Volt/m$
Seven capacitors, each of capacitance $2\,\mu F$ are to be connected to obtain a capacitance of $10/11\,\mu F$ .Which of the following combinations is possible ?
Two thin wire rings each having a radius $R$ are placed at a distance $d$ apart with their axes coinciding. The charges on the two rings are $+ q$ and $-q$. The potential difference between the centres of the two rings is