Question

The equivalent capacitance of the combination shown in figure (31-Q1) is
(a) C
(b) 2 C
(c) C/2
(d) none of these.

Answer 1

(b) 2C



Since the potential at point A is equal to the potential at point B, no current will flow along arm AB. Hence, the capacitor on arm AB will not contribute to the circuit. Also, because the remaining two capacitors are connected in parallel, the net capacitance of the circuit is given by
C_eq = C + C = 2C