Question

Seven capacitors each of capacitance $2\mu F$ are to be connected to obtain a capacitance of $\left(\frac{10}{11}\right)\mu F$. Which of the following combination will be used for this purpose?

• A. 5 resistances in parallel 2 in series
• B. 4 resistances in parallel 3 in series
• C. 3 resistances in parallel 4 in series
• D. 2 resistances in parallel 5 in series

Answer 1

The correct option is A 5 resistances in parallel 2 in series

Two capacitors are conected in series,
$C=\frac{C_1{C}_2}{C_1+C_2}=\frac{4}{2+2}=1\mu F$
Five capacitors are connected in parallel, so $C_p=5\left(2\right)=10\mu F$
Effective capacitance is
$\therefore C_{net}=\frac{\left(10\right)\left(1\right)}{10+1}=\frac{10}{11}\mu F$
hence (a) is correct.