The figure shows a capacitor of capacitance $\mathrm{C}$ connected to a battery via a switch, having a total charge ${\mathrm{Q}}_0$ on it, in steady-state. When the switch $\mathrm{S}$ is turned from position $\mathrm{A}$ to position $\mathrm{B}$, the energy dissipated in the circuit is

The diagram shows the arrangement of three small uniformly charged spheres $A$, $B$ and $C$. The arrows indicate the direction of the electrostatic forces acting between the spheres (for example, the left arrow on sphere $A$ indicates the electrostatic force on sphere $A$ due to sphere $B$). At least two of the spheres are positively charged. Which sphere, if any, could be negatively charged?

Four charges are placed at the circumference of a dial clock as shown in the figure. If the clock has only hour hand and a charge $q_0$ is placed at the center, then the hour hand points in the direction which shows the time as