Why can an inductor store energy for so long

How does an inductor store energy?

An inductor stores energy in its magnetic field. As the current through the inductor increases, it forces the magnetic lines of force to expand against their natural tendency to shorten. This expansion stores energy in the magnetic field, similar to how a rubber band stores energy when stretched.

Do inductors store energy in a magnetic field?

Like Peter Diehr says in the comments, the way to see the duality between inductors and capacitors is that capacitors store energy in an electric field, inductors store energy in a magnetic field. But if we cut off current, will the magnetic field stay there?

When does the energy stored by an inductor stop increasing?

The energy stored by the inductor increases only while the current is building up to its steady-state value. When the current in a practical inductor reaches its steady-state value of Im = E/R, the magnetic field ceases to expand.

How is the energy stored in an inductor calculated?

The energy stored in the magnetic field of an inductor can be written as E = 0.5 * L * I^2, where L is the inductance and I is the current flowing through the inductor.

What happens if we continuously give current to an inductor?

Also, if we continuously give current to an inductor, it will create a continuously increasing magnetic field until it reaches a maximum and stop the flow of current, similar to what capacitors do? As capacitors store energy in the electric field, so inductors store energy in the magnetic field.

How does a pure inductor work?

This energy is actually stored in the magnetic field generated by the current flowing through the inductor. In a pure inductor, the energy is stored without loss, and is returned to the rest of the circuit when the current through the inductor is ramped down, and its associated magnetic field collapses. Consider a simple solenoid.