Two identical coils of inductance $L$ joined in series are placed very close to each other such that the winding direction of one coil is exactly opposite to that of the other. The net inductance is

When a current in the conducting coil is changed from 5 A in one direction to 5 A in opposite direction in 0.5 second, an average induced e.m.f in the coil is 2 V . The selfinductance of the coil is

Figure shows the north pole of a magnet moving away from a thick conducting loop containing a capacitor. The excess positive charge will arrive on

A graph of magnetic flux $(\phi)$ versus current $(I)$ is shown for four inductors $\mathrm{P}, \mathrm{Q}, \mathrm{R}, \mathrm{S}$. The largest value of self-inductance is for inductor