An arc lamp requires a direct current of $10\ A$ at $80\ V$ to function. If it is connected to a $220\ V$ (rms),$50\ Hz$ $AC$ supply,the series inductor needed for it to work is close to: (in $H$)

In the given figure,the current amplitude is

$A$ coil has a resistance of $30\,\Omega$ and an inductive reactance of $20\,\Omega$ at a frequency of $50\,Hz$. If an $AC$ source of $200\,V$ and $100\,Hz$ is connected across the coil,the current in the coil will be.......$A$

An electric bulb,an open coil inductor,an $AC$ source,and a key are all connected in series to form a closed circuit. The key is closed and after some time,an iron rod is inserted into the interior of the inductor. Then:

For the given $RL$ circuit,the maximum power loss across the circuit can be $W$.

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