List of top Physics Questions on Combination of capacitors asked in AIIMS

Two spherical conductors $A$ and $B$ of radii $a$ and $b(b>a)$ are placed concentrically in air. The two arc connected by a copper wire as shown in figure. The equivalent capacitance of the system is

A network of four capacitors of capacities equal to $C_{1}=C, C_{2}=2 C, C_{3}=3 C$ and $C_{4}=4 C$ are connected to a battery as shown in the figure.

The ratio of the charges on $C_{2}$ and $C_{4}$ is