Three inductances are connected as shown in the figure. The equivalent inductance between A and b is

The current flowing through an inductor of selfinductance L is continuously increasing at constant rate. The variation of induced e.m.f. (e) verses $\mathrm{dI} / \mathrm{dt}$ is shown graphically by figure

The coefficient of mutual induction is 2 H and induced e.m.f. across secondary is 2 kV . Current in the primary is reduced from 6 A to 3 A . The time required for the change of current is

Two planar concentric rings of metal wire having radii $\mathrm{r}_1$ and $\mathrm{r}_2\left(\mathrm{r}_1>\mathrm{r}_2\right)$ are placed in air. The current I is flowing through the coil of larger radius. The mutual inductance between the coils is given by ( $\mu_0=$ permeability of free space)