Two charged spheres of radii $R_1$ and $R_2$ having equal surface charge density. The ratio of their potential is

Five indentical capacitor plates, each of area $A,$ are arranged such that adjacent plates are at distance $d$ apart. The plates are connected to a source of $emf$ $V$ as shown in fig. Then the charges $1$ and $4$ are, respectively :-

Four identical capacitors are connected in series with a battery of $emf$ $10\,V$. The point $X$ is earthed, then the potential of point $A$ is.....$V$

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

Consider a cube of uniform charge density $\rho$. The ratio of electrostatic potential at the centre of the cube to that at one of the corners of the cube is

Charge of $2Q$ and $-Q$ are placed on two plates of a parallel plate capacitor if capacitance of capacitor is $C$ find potential difference between the plates