In the figure, a potential of $+1200\, V$ is applied to point $A$ and point $B$ is earthed. What is the potential at point $P$ in volts?

$A$ capacitor $C_1 = 1\,\mu F$ can withstand a maximum voltage of $V_1 = 6\,kV$,and a capacitor $C_2 = 3\,\mu F$ can withstand a maximum voltage of $V_2 = 4\,kV$. If these two capacitors are connected in series,what is the maximum voltage (in $kV$) that can be applied to the combination?

Consider an infinite matrix of capacitors as shown in the figure. The effective capacitance between point $A$ and $B$ will be

$A$ radioactive substance in the form of a metallic sphere of diameter $10^{-3} \ m$ emits particles at a constant rate of $6.25 \times 10^{10}$ particles per second. If the sphere is electrically isolated,how long will it take for its potential to increase by $1.0 \ V$? Assume that $80\%$ of the emitted particles escape from the surface. The time taken is $... \mu s$.

Three large plates are arranged as shown. How much charge will flow through the key $K$ if it is closed?

Calculate the charge on the capacitor in the steady state. (in $\mu C$)