$A$ coil has inductance $L$. The ratio of its reactance when it is connected first to an $A.C.$ source and then to a $D.C.$ source is

In a choke coil,the reactance $X_L$ and resistance $R$ are such that

An inductor is connected to an $AC$ source of frequency $50 \ Hz$. The frequency of the instantaneous power developed in the circuit is (in $Hz$)

The inductive reactance of a coil is $R$. If the inductance of the coil is doubled and the frequency of the $A.C.$ supply is also doubled,then the new inductive reactance will be:

$A$ $70 mH$ inductor is connected to a $220 V, 50 Hz$ $AC$ supply. The rms value of the current in the circuit is:

$A$ coil of inductance $L$ has an inductive reactance of $X_L$ in an $AC$ circuit in which the effective current is $I$. The coil is made from a superconducting material and has no resistance. The rate at which power is dissipated in the coil is