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?

Three capacitors are connected to a battery as shown in the figure. The ratio of charge on capacitors $C_3$ and $C_1$ is (in $.5$)

Find the potential difference between $A$ and $B$ in the given circuit in the steady state. (in $V$)

Three concentric conducting spherical shells have radii $r, 2r$ and $3r$ and $Q_1, Q_2$ and $Q_3$ are final charges respectively. The innermost and outermost shells are earthed as shown in the figure. Choose the wrong statement.

If a capacitor of capacitance $100 \mu F$ is charged at a steady rate of $100 \mu C s^{-1}$,then the time taken to produce a potential difference of $100 \ V$ between the capacitor plates is (in $s$)

$A$ capacitor is made of two circular plates of radius $R$ each,separated by a distance $d \ll R$. The capacitor is connected to a constant voltage $V$. $A$ thin conducting disc of radius $r \ll R$ and thickness $t \ll r$ is placed at the center of the bottom plate. Find the minimum voltage required to lift the disc if the mass of the disc is $m$.