$A$ small conducting sphere is hung by an insulating thread between the plates of a parallel plate capacitor as shown in the figure. The net force on the sphere is

$A$ charge of $Q$ coulomb is placed on a solid piece of metal of irregular shape. The charge will distribute itself:

Assertion: $A$ positive charge particle is placed in front of a spherical uncharged conductor. The number of lines of force 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.

$A$ hollow metal sphere of radius $R$ is charged with a charge $Q$. The electric potential and intensity inside the sphere are respectively

Consider an initially neutral hollow conducting spherical shell with inner radius $r$ and outer radius $2r$. $A$ point charge $+Q$ is now placed inside the shell at a distance $r/2$ from the centre. The shell is then grounded by connecting the outer surface to the earth. $P$ is an external point at a distance $2r$ from the point charge $+Q$ on the line passing through the centre and the point charge $+Q$ as shown in the figure. The magnitude of the force on a test charge $+q$ placed at $P$ will be

$A$ point charge $q$ is placed in a cavity in a metal block. If a charge $Q$ is brought outside the metal,then the electric force experienced by $q$ is