HOW DOES AN INDUCTOR BLOCK AC AND PASS DC?

 why does an inductor block AC and pass DC

Inductance is in fact property of a conductor by which the change in current trough it, induce in electromotive force either in self inductance or in other nearby conductor's (mutual inductance).

according to oersted's low a steady current produce a steady magnetic field, As the current across the inductor varies the magnetic field becomes time varying.

here is the application of the faradays low a time varying magnetic field induce an electromotive force (voltage), Thus an electromotive force induce is induced in the conductor or near by conductors by the process of inductance.

This is to the proportional of the magnetic field and finally the change in current.    Thus self inductance given by the expressions.

v(t)=L di/dt

where  v(t) is the voltage across and i is the current trough it,                                                  L is the proportionality constant is called self inductance.

Now the point is that by len'z low this induced voltage must oppose the cause i.e. the current flow it and hence the voltage applied

so as we provided ac to an inductor the change in current of ac induce a voltage and this causes the blocking AC by inductor.

The same thing also be realised from the reactance concept                                        which is derived from the above expression and given as

X=2piFL

where X is the reactance of the inductance and L is the self inductance.

The inductive reactance proportional to the frequency and self inductance.              Thus the higher the frequency the higher the reactance.

since reactance is the phasor major of resistance,                                                            It  can be thus said that an inductor will block AC.

di/dt=V/L

rate of change of current is proportional to Voltage and inversely proportional to inducatance.

If you apply dc across an inductor you it will stabilize to some current flow based on the maximum current available from the current voltage source  in this mode the inductor present very low resistance, so it can be said that it allow to DC pass