An $AC$ circuit having supply voltage $E = 10 \sin \omega t$ consists of a resistor of resistance $R = 3 \Omega$ and an inductor of reactance $X_L = 4 \Omega$ as shown in the figure. The voltage across the inductor at $t = \pi / \omega$ is: (in $\text{ V}$)

The following series $L-C-R$ circuit,when driven by an emf source of angular frequency $70 \text{ krad/s}$,behaves effectively as:

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:

In an $L-C-R$ circuit,the potential difference across the inductor is $60\,V$,across the capacitor is $30\,V$,and across the resistor is $40\,V$. The supply voltage will be: (in $,V$)

An inductance coil has a reactance of $100\, \Omega$. When an $AC$ signal of frequency $1000\, Hz$ is applied to the coil,the applied voltage leads the current by $45^{\circ}$. The self-inductance of the coil is

$A$ coil having an inductance of $\frac{1}{\pi} \text{ H}$ is connected in series with a resistance of $300 \text{ } \Omega$. If $20 \text{ V}$ from a $200 \text{ Hz}$ source are impressed across the combination,the value of the phase angle between the voltage and the current is