A solid spherical conducting shell has inner radius a and outer radius $2a$. At the center of the shell a point charge $+Q$ is located . What must the charge of the shell be in order for the charge density on the inner and outer surfaces of the shell to be exactly equal?

The electric flux from a cube of edge $l$ is $\phi $. If an edge of the cube is made $2l$ and the charge enclosed is halved, its value will be

The force on a charge situated on the axis of a dipole is $F$. If the charge is shifted to double the distance, the new force will be

In the given circuit if point $C$ is connected to the earth and a potential of $+2000\,V$ is given to the point $A$ , the potential of $B$ is.....$V$

Four point $+ve$ charges of same magnitude $(Q)$ are placed at four corners of a rigid square frame in $xy$ plane as shown in figure. The plane of the frame is perpendicular to $z-$ axis. If a $-ve$ point charges is placed at a distance $z$ away from the above frame $(z << L)$ then

Assertion : The positive charge particle is placed in front of a spherical uncharged conductor. The number of lines of forces terminating on the sphere will be more than those emerging from it.

Reason : The surface charge density at a point on the sphere nearest to the point charge will be negative and maximum in magnitude compared to other points on the sphere