A series combination of $n_1$ capacitors, each of value $C_1$, is charged by a source of potential difference $4V$. When another parallel combination of $n_2$ capacitors, each of value $C_2$, is charged by a source of potential difference $V$ , it has the same (total) energy stored in it, as the first combination has. The value of $C_2$ , in terms of $C_1$, is then
$\frac {2C_1}{n_1n_2}$
$16\frac{{{n_2}}}{{{n_1}}}{C_1}$
$2\frac{{{n_2}}}{{{n_1}}}{C_1}$
$\frac {16C_1}{n_1n_2}$
Electric flux through surface $s_1$ :-
A hollow metal sphere of radius $5\,cm$ is charged such that the potential on its surface is $10\,V$. The potential at a distance of $2\,cm$ from the centre of the sphere.......$V$
An electric dipole is placed along the $x$ -axis at the origin $O.$ A point $P$ is at a distance of $20\, cm$ from this origin such that $OP$ makes an angle $\frac{\pi}{3}$ with the $x$ -axis. If the electric field at $P$ makes an angle $\theta$ with the $x$ -axis, the value of $\theta$ would be
Five conducting parallel plates having area $A$ and separation between them $d$, are placed as shown in the figure . Plate number $2$ and $4$ are connected wire and between point $A$ and $B$, a cell of emf $E$ is connected . The charge flown through the cell is :-
Two capacitors $C_1$ and $C_2$ are are charged to $120\, V$ and $200\, V$ respectively. It is found that by connecting them together the potential on each one can be made zero . Then