Obtain relation between drift velocity and current density.

Calculate the potential difference plate $\mathrm{A} \mathrm{and} \mathrm{B}$ of the capacitor in the following circuit

The figure shows a part of a closed circuit. If the current flowing through it is $2 \mathrm{A}$ then $V_B-V_A$ is _______

Five pure inductors each of $3 \mathrm{H}$ are connected as shown in figure. The equivalent inductance of this connection between points $\mathrm{A}$ and $\mathrm{B}$ is _____.