$A$ series $LCR$ circuit consists of $R = 80\,\Omega$,$X_{L} = 100\,\Omega$,and $X_{C} = 40\,\Omega$. The input voltage is $V = 2500 \cos(100\pi t)\,V$. The amplitude of current in the circuit is $................A$.

The time constant of the given $LR$ circuit is $\tau$. If the battery is replaced by an $AC$ source having voltage $V = V_0 \cos \omega t$,the power factor of the circuit will be

An inductor and a resistor are connected in series to an ac supply. If the potential differences across the inductor and the resistor are $180 \ V$ and $240 \ V$ respectively,then the voltage of the ac supply is (in $V$)

In the given circuit,the angular frequency of the voltage source is $70 \times 10^3 \text{ rad s}^{-1}$. The circuit effectively behaves like,

If the power factor is $1/2$ in a series $RL$ circuit with $R = 100\,\Omega$ connected to an $ac$ mains $(50\,Hz)$,find the value of $L$.

An inductor and a resistor are connected in series to an ac source of variable frequency. When the frequency of the applied ac is $50 \ Hz$,the power factor of the circuit is $\frac{\sqrt{3}}{2}$. If the frequency of the ac is increased by $200 \%$,the power factor of the circuit is . . . . . . .