Five capacitors of $10\,\mu F$ capacity each are connected to a $d.c.$ potential of $100\;V$ as shown in the figure. The equivalent capacitance between the points $A$ and $B$ will be equal to..........$\mu F$.

What is the total electrostatic potential energy of the given system in $J$? (Given: $\frac{1}{{4\pi {\varepsilon _0}}} = 9 \times {10^9} \ N \cdot m^2/C^2$)

$(a)$ $A$ $900 \; pF$ capacitor is charged by a $100 \; V$ battery [Figure $(a)$]. How much electrostatic energy is stored by the capacitor?
$(b)$ The capacitor is disconnected from the battery and connected to another $900 \; pF$ capacitor [Figure $(b)$]. What is the electrostatic energy stored by the system?

$A$ soap bubble is given a negative charge,then its radius

$A$ parallel plate capacitor is charged and then disconnected from the source of steady $E.M.F.$ The plates are then drawn apart farther. Again it is connected to the same source. Then:

Two capacitors of equal capacitance $(C_1 = C_2)$ are shown in the figure. Initially,while the switch $S$ is open,one of the capacitors is uncharged and the other carries charge $Q_0$. The energy stored in the charged capacitor is $U_0$. After the switch is closed,the capacitors $C_1$ and $C_2$ carry charges $Q_1$ and $Q_2$,respectively; the voltages across the capacitors are $V_1$ and $V_2$; and the energies stored in the capacitors are $U_1$ and $U_2$. Which of the following statements is $INCORRECT$?