Two identical conductors of copper and aluminium are placed in identical electric fields. The magnitude of induced charge in the aluminium will be

$A$ 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

Two concentric spherical shells of radius $R_1$ and $R_2$ have $q_1$ and $q_2$ charge respectively as shown in the figure. How much charge will flow through key $k$ when it is closed?

The metal plate on the left in the figure carries a charge of $+q$. The metal plate on the right has a charge of $-2q$. What charge will flow through the switch $S$ when it is closed,if the central plate is initially neutral?

Two uniformly charged spherical conductors $A$ and $B$ of radii $5 \ mm$ and $10 \ mm$ are separated by a distance of $2 \ cm$. If the spheres are connected by a conducting wire,then in equilibrium condition,the ratio of the magnitudes of the electric fields at the surface of the sphere $A$ and $B$ will be.

$A$ charge $q$ is placed at $O$ in the cavity of a spherical uncharged conductor. Point $S$ is outside the conductor. If the charge is displaced from $O$ towards $S$ while still remaining within the cavity,then: