Two charged conducting spheres of radii $a$ and $b$ are connected to each other by a conducting wire. The ratio of charges of the two spheres respectively is:

Conduction electrons are almost uniformly distributed within a conducting plate. When placed in an electrostatic field $\overrightarrow{E}$,the electric field within the plate

What is a Van de Graaff generator? Explain its principle.

$A$ 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:

Which of the following statements is always true for a charged conductor?
$(1)$ The electric field just outside the surface is parallel to the surface.
$(2)$ $E_{in} = 0$
$(3)$ Electric field lines are perpendicular to the equipotential surface.

Four very large metal plates are given the charges as shown in the figure. The middle two plates are then connected through a wire. Find the charge that will flow through the wire.