How an inductor works?

The inductor is behaving the way it does? Assume that we are applying a DC voltage across its terminals, no current passes through it initially, then after some time it starts building up.

In case of inductor the produced emf will depend on the (di/dt).

v = L(di/dt);

Now if you put a dc voltage, then initially there was no voltage across the inductor. Just after you put the battery, you get a voltage v across it.

Now di/dt = v/L

i = ⌠(v/L)dt;

and i(0) = 0;

So you get i(t) = vt/L;

When a dc voltage is applied across an inductor, initially when time T=0,no current flows through it . What exactly is preventing the current from flowing? If it is the back emf(which in turn is due to a change in magnetic field),how is it possible to have a change in the magnetic field without any current flowing.

How is it possible to have a change in the magnetic field without any current flowing?

The back emf does not depend on i, but on (di/dt).

At t=0;

i=0;

But di/dt = V/L;

So it can produce the back emf.

1) Suppose you through a ball on the sky. At the top most point the velocity of the ball becomes zero. But there (dv/dt)=-g.

2) Let there is a magnet. In front of it there is a magnetic screen. and after that there is a iron ball. Now initially the ball is not attracted by the magnetic field as there is the magnetic screen. So its velocity is zero. Now let at the time t=0, you remove the screen. So just at t=0 the ball gets attracted by the magnet. Now what the ball will do? Will the ball go towards the magnet or it remains still? (Consider that there is no other force acting on the ball)

It starts off as V= line voltage, and if there is a resistance in the circuit somewhere then winds up as V=0 when t->1/0.

 

 


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