Question

Four equal capacitors, each with a capacitance $C$ are connected to battery of E.M.F. $10V$ as shown in the figure. The midpoint of the capacitor system is connected to the earth. Then, the potentials of B and D are, respectively :

• A. +10 V, zero V
• B. +5 V, -5 V
• C. -5 V, +5 V
• D. zero V, 10 V

Answer 1

The correct option is B +5 V, -5 V

When capacitors are connencted in series , charge on each capacitor is equal to the equivalent charge.
$C_{eq}^{12}=\frac{CC}{C+C}=C/2$,

$Q_{eq}^{12}=\left(C/2\right)10=5CV$
thus , $V_1=\frac{Q_{eq}^{12}}{C}=5V$
Thus $V_B=5V$
similarly, $V_4=-5V$, thus $V_D=-5V$