An a. c. source is connected across a pure inductor. Which one of the following figures shows the correct phase relation between the current and e.m.f.?

In an a.c. circuit with pure capacitance ' C ' and a.c. source $E=E_0 \sin \omega t$, the equation of instantaneous current is given by

A current of 5 A is flowing at 220 V in a primary coil of a transformer. If the voltage produced in the secondary coil is 2200 V and $50 \%$ of power is lost, then the current in the secondary coil will be

Figure shows the combination of inductances and capacitances. Resonant frequency of the $\mathrm{L}-\mathrm{C}$ circuit is