In a L-R circuit of 4 mH inductance and $3\ \Omega$ resistance, e.m.f. $E = \cos(1000t)$ V is applied. The amplitude of current is

A current of 4 A is flowing at 230 V in the primary coil of a transformer. If the voltage produced in the secondary coil is 2300 V and 40 % of power is lost, then the current in the secondary will be

In a series LCR circuit, the voltage across R is $100$ V, $R = 1\,\text{K}\,\Omega$ and $C = 2\,\mu\text{F}$. The angular frequency $\omega$ is $200$ rad s$^{-1}$. At resonance, the voltage across '$L$' is

Which graph shows the correct variation of r.m.s. current '$i$' with frequency '$f$' of a.c. in case of series resonant circuit ?