Find the equivalent capacitance across points $A$ and $B$.

The figure shows the charge $(q)$ versus voltage $(V)$ graph for series and parallel combinations of two given capacitors. The capacitances are:

Find the net capacitance between $A$ and $B$.

For the arrangement of capacitors as shown in the circuit,the effective capacitance between the points $A$ and $B$ is (capacitance of each capacitor is $4 \mu F$): (in $\mu F$)

Two parallel plate capacitors are connected in series. Each capacitor has a plate area $A$ and a separation $d$ between the plates. The dielectric constants of the media between their plates are $2$ and $4$. The separation between the plates of a single air capacitor of plate area $A$ which effectively replaces the combination is:

The equivalent capacitance between $A$ and $B$ is (in $\mu F$):