Four identical capacitors each of capacitance C are arranged as shown in the figure. What is the effective capacitance between P and Q?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → \( \frac{5C}{3} \)
Capacitances add directly in parallel and their reciprocals add in series.
From the figure, \( C_1 \) and \( C_2 \) are in parallel; this pair is in series with \( C_3 \) in the lower branch; and the lower branch is in parallel with \( C_4 \) in the upper branch, between P and Q.
\( C_1 \parallel C_2: \ C + C = 2C \)
\( \displaystyle 2C \text{ in series with } C_3: \ \frac{2C \times C}{2C + C} = \frac{2C}{3} \)
\( \displaystyle C_{\mathrm{eff}} = \frac{2C}{3} + C_4 = \frac{2C}{3} + C = \frac{5C}{3} \)