If the power factor changes from $0.5$ to $0.25$ because impedance changes from $Z_1$ to $Z_2$, then $Z_1 = x Z_2$. The value of $x$ is (Resistance remains constant).

$A$ $LCR$ series circuit driven with $V_{rms} = 90 \text{ V}$ at frequency $f_d = 30 \text{ Hz}$ has resistance $R = 80 \text{ }\Omega$,an inductance with inductive reactance $X_L = 20.0 \text{ }\Omega$ and capacitance with capacitive reactance $X_C = 80.0 \text{ }\Omega$. The power factor of the circuit is . . . . . . .

For an $AC$ circuit,the potential difference and current are given by $V = 10 \sqrt{2} \sin \omega t$ (in $V$) and $I = 2 \sqrt{2} \cos \omega t$ (in $A$) respectively. The power dissipated in the instrument is ............ $W$.

Write an equation of average power for $L-C-R$ series $AC$ circuit and discuss its various cases.

In an $AC$ circuit,the $emf$ $(e)$ and the current $(i)$ at any instant are given respectively by:
$e = E_{0} \sin \omega t$
$i = I_{0} \sin (\omega t - \phi)$
The average power in the circuit over one cycle of $AC$ is:

If a current $I$ given by $I = I_0 \sin(\omega t - \frac{\pi}{2})$ flows in an $AC$ circuit across which an $AC$ potential of $E = E_0 \sin(\omega t)$ has been applied,then the power consumption $P$ in the circuit will be