In a series $LCR$ circuit,the resistance is $18 \ \Omega$ and the impedance is $33 \ \Omega$. An $r.m.s.$ voltage of $220 \ V$ is applied across the circuit. The true power consumed in the $a.c.$ circuit is: (in $W$)

The figure shows an $LCR$ series $AC$ circuit. If $L$ is removed from the circuit,the current leads the voltage by $45^o$,while if $C$ is removed,the current lags the voltage by $45^o$. The current passing in the original circuit is......$A$.

What is the impedance of an $L-C-R$ series $AC$ circuit?

$A$ rejector circuit is the resonant circuit in which

Two coils require $20 \ min$ and $60 \ min$ respectively to produce the same amount of heat energy when connected separately to the same source. If they are connected in parallel to the same source,the time required to produce the same amount of heat by the combination of coils will be . . . . . . $min$.

How does the sign of the phase angle $\phi$,by which the supply voltage leads the current in an $LCR$ series circuit,change as the supply frequency is gradually increased from very low to very high values?