Question

The equivalent capacitance between P and Q of the given figure is (the capacitance of each capacitor is$1\mu F$ ):

• A. $2\mu F$
• B. $0.5\mu F$
• C. $5\mu F$
• D. $0.2\mu F$

Answer 1

The correct option is B $0.5\mu F$

We know when capacitors are in series:

$\frac{1}{C_{eff}}=\frac{1}{C_1}+\frac{1}{C_2}$
and when in parallel:

$C_{eff}=C_1+C_2$

So, for the given combination, between P and Q there are 2 combinations of 2 parallely connected capacitors and these combinations come in series with a single capacitor.

So, effective capacitance between P and Q may expressed as:

$\frac{1}{C_{eff}}=\frac{1}{2C}+\frac{1}{C}+\frac{1}{2C}$
or, $C_{eff}=\frac{C}{2}$$=0.5C$
$\therefore C_{eff}=0.5\mu F$