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 spheres $A$ and $B$ are kept very near to each other. $A$ is negatively charged and $B$ is earthed. The true statement is:
$(A)$ Charge on $B$ is zero
$(B)$ Potential at $B$ is zero
$(C)$ Charge is uniformly distributed on $A$
$(D)$ Charge is non-uniformly distributed on $A$

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

The radii of two metallic spheres $A$ and $B$ are ${r_1}$ and ${r_2}$ respectively $({r_1} > {r_2})$. They are connected by a thin wire and the system is given a certain charge. The charge will be greater:

$A$ metallic rod is placed in a uniform electric field. Select the correct option.

Which of the following statements are correct?
$A$. Inside the conductor,the electrostatic field is zero.
$B$. Electric field at the surface of a charged conductor does not depend on its surface charge density.
$C$. The interior of a charged conductor can have no excess charge in the static situation.
$D$. At the surface of a charged conductor,the electrostatic field must be normal to the surface at every point.
$E$. The electrostatic potential is zero everywhere inside a charged conductor.
Choose the correct answer from the options given below: