Physics - Capacitor Question with Solution | TestHub

Equivalent circuit, uing potential at $\mathrm{P}$ is same as at $\mathrm{A}$ and potential at $R$ is same as at $B$.This is equivalent to following:Therefore, the equivalent capacitance across AB is given by, $$\Rightarrow C_{AB}=C+\frac{C}{2}+\frac{C}{2}=2C$$