For an $AC$ circuit $V = 15 \sin \omega t$ and $I = 20 \cos \omega t$,the average power consumed in this circuit is ..... $W$.

In a series $LCR$ circuit,the inductive reactance $(X_{L})$ is $10\, \Omega$ and the capacitive reactance $(X_{C})$ is $4\, \Omega$. The resistance $(R)$ in the circuit is $6\, \Omega$. The power factor of the circuit is :

Assertion $(A):$ If the frequency of the applied $AC$ is doubled,then the power factor of a series $R-L$ circuit decreases.
Reason $(R):$ Power factor of series $R-L$ circuit is given by $\cos \theta = \frac{R}{\sqrt{R^2 + \omega^2 L^2}}$.

What will be the phase difference between virtual voltage and virtual current when current in the circuit is wattless (in $^{\circ}$)?

The instantaneous values of current and potential difference in an alternating circuit are $i = \sin \omega t$ and $E = 100 \cos \omega t$ respectively. The $r.m.s.$ value of the wattless current (in $A$) in the circuit is:

$A$ series $LCR$ circuit is connected to an $AC$ source of $220\,V, 50\,Hz$. The circuit contains a resistance $R = 80\,\Omega$,an inductor of inductive reactance $X_L = 70\,\Omega$,and a capacitor of capacitive reactance $X_C = 130\,\Omega$. The power factor of the circuit is $\frac{x}{10}$. The value of $x$ is: