The impedance of an $LR$ circuit with $L=\frac{60}{\pi} \text{ mH}$,$R=8 \Omega$ and frequency $f=50 \text{ Hz}$ is (in $\Omega$)

In the circuit shown,if the $emf$ of the source at an instant is $5 \, V$,and the potential difference across the capacitor at the same instant is $4 \, V$,then the potential difference across $R$ at that instant may be ..... $V$.

In the circuit shown below,the $ac$ source has voltage $V = 20\cos (\omega t)$ volts with $\omega = 2000 \,rad/sec$. The amplitude of the current will be nearest to:

An $AC$ source of angular frequency $\omega$ is connected across a resistor $R$ and a capacitor $C$ in series. The current flowing in the circuit is found to be $I$. Now,the frequency of the source is changed to $\frac{\omega}{3}$ (maintaining the same voltage),and the current in the circuit is found to be halved. What is the ratio of reactance to resistance at the original frequency?

The phase difference between the alternating current and emf is $\frac{\pi}{2}$. Which of the following cannot be the constituent of the circuit?

An inductive circuit contains a resistance of $10 \, \Omega$ and an inductance of $2.0 \, H$. If an $AC$ voltage of $120 \, V$ and frequency $60 \, Hz$ is applied to this circuit,the current would be nearly: ..... $A$