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:

Three identical uncharged metal spheres are at the vertices of an equilateral triangle. One at a time,a small sphere is connected by a conducting wire with a large metal sphere that is charged. The center of the large sphere is on the straight line perpendicular to the plane of the equilateral triangle and passing through its center (see figure). As a result,the first small sphere acquires charge $q_1$ and the second acquires charge $q_2$ $(q_2 < q_1)$. The charge that the third sphere $q_3$ will acquire is (Assume $l >> R$,$l >> r$,$d >> R$,$d >> r$):

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.

Explain the construction of a Van de Graaff generator with a diagram and describe its uses.

Two conductors of the same shape and size,one of copper and the other of aluminium (which is less conducting),are placed in a uniform electric field. What can be said about the charge induced in the aluminium conductor?

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?