In the $A$.$C$. circuit shown,keeping switch $K$ closed,if an iron rod is inserted into the coil,the bulb in the circuit:

For a series $LCR$ circuit,which one of the following is a $CORRECT$ statement?

An e.m.f. $E = E_{0} \sin \omega t$ is applied to a circuit containing $L$ and $R$ in series. If $X_{L} = R$,then the power dissipated in the circuit is

$A$ student connects a long air-cored coil of manganin wire to a $100 \ V$ $DC$ supply and records a current of $25 \ A$. When the same coil is connected across a $100 \ V, 50 \ Hz$ $AC$ supply,the current reduces to $20 \ A$. The reactance of the coil is $...... \Omega$.

In a series $LCR$ circuit,$R=300 \Omega$,$L=0.9 \text{ H}$,$C=2 \mu\text{F}$,and $\omega=1000 \text{ rad/s}$. The impedance of the circuit is: (in $\Omega$)

In a simple $L-R$ circuit with an $A.C.$ source,the potential difference at any instant across the inductor and the resistor are $V_L$ and $V_R$ respectively,and the $A.C.$ source has a potential difference $V_{AC}$ at the same instant. Then: