Question

In the figure shown below, the charge on the left plate of the $10uF$ capacitor is $-30uF$. The charge on the right plate of the $6uF$ capacitor is:

• A. $-18uF$
• B. $-12uF$
• C. $+12uF$
• D. $+18uF$

Answer 1

The correct option is D

$+18uF$

Step 1: Given information

The capacitance of capacitors used in the circuit is,

$C_1=10uF,C_2=6uF,C_3=4uFand{C}_4=2uF$

The charge on the left plate of the $10uF$ capacitor = $-30uF$

Step 2: Diagram

Step 3: Calculation of the charge on the right plate

Since, $6\mu F\&4\mu F$ are in parallel & the total charge on this combination is $30\mu C$,

Therefore, Charge on,

$$\begin{gathered} 6\mu Fcapacitor=\left[\frac{6}{(6+4)}\right]x30 \\ 6\mu Fcapacitor=6\mu F \end{gathered}$$.

Therefore, the net capacitance of $6\mu F$ and $10\mu F$ capacitors$=10\mu F$, and charge on $6\mu F$ capacitor plate$=\frac{6}{10}\times 30$

$=18\mu F$

Since the charge is asked on the right plate therefore is $+18\mu C$.

Hence, the correct option is (D).