# Electron Flow Creates Magnetic Field Around Coil with Permanent Magnet

• likephysics
In summary, a moving electron causes a magnetic field and any wire with current flow has a magnetic field around it. When a permanent magnet is brought near a coil, current flows initially and then the induced magnetic field opposes the magnet's field. The current must be flowing in the wire to keep the induced field active. We can make use of this current to light a bulb or charge a small battery. However, for induction to occur, a changing magnetic field is necessary. The induction in the coil is not because of the magnet's proximity but due to the relative motion between the magnet's field and the inductor. The energy in electricity comes from the energy expended in moving the magnet or the coil. This induction is also used in devices like
likephysics
A moving electron causes a magnetic field. So any wire with current flow has mag field around it.
When a Permanent magnet is bought near a coil, current flows initially and then the induced mag field opposes the PM field.
For the induced field to exist, electrons must be flowing through the wire. correct?

yes. the current must be flowing the wire to keep induced field active.

KnowPhysics said:
yes. the current must be flowing the wire to keep induced field active.

well then, we can make use of that current to light a bulb or charge a small battery?

likephysics said:
well then, we can make use of that current to light a bulb or charge a small battery?

Yes, of course.

If current is already flowing in the coil, then why do we need changing magnetic field?

So you were asking whether a current has to exist previously in the coil, in order for induction to occur when you move the permanent magnet? In that case, the answer is "no."

All I am asking is why do we require a changing Magnetic field for induction to occur?
Current is already flowing when the PM is close to the coil.

The fact that a time-changing ac magnetic field produces induction, and a steady dc magnetic field does not, is an axiom. There is no formal proof in terms of anything more fundamental. This is a postulated fact based on empirical observation which has been consistent under all known conditions since day one with no exceptions ever found. Does this help?

Claude

likephysics said:
All I am asking is why do we require a changing Magnetic field for induction to occur?
Current is already flowing when the PM is close to the coil.

Don't get confused. The induction in the coil is completely different. it is because of the current flowing through the wire it is nothing to do with your PM. if you want to produce induction with PM then the magnet must move (the magnetic field will cut by wire it will produce induction in wire).

likephysics said:
All I am asking is why do we require a changing Magnetic field for induction to occur?
Current is already flowing when the PM is close to the coil.

When one magnetic field remains motionless relative to another, voltage induction cannot occur. Voltage induction requires a change in the physical movement or change of intensity of a magnetic field or the movement of a conductor cutting through a magnetic field. For a continual voltage to be induced, a continually change in these factors must occur on a continual basis.

likephysics said:
All I am asking is why do we require a changing Magnetic field for induction to occur?
Current is already flowing when the PM is close to the coil.

Current does not flow because of the PM's proximity to the coil, it flows because of the relative motion between the PM's field and the inductor. Current will only flow while you are moving the PM toward or away from the coil.

If you put a magnet near a coil and then let them both sit still, there will be no current whatever while they are sitting still.

The energy in electricity comes from the energy expended in moving the magnet or the coil, not from anything else. The special property of a magnetic field is that it can interact with, and put pressure on, the free electrons in the conductor: if we move the magnetic field relative to the conductor it will cause electrons to move. If we don't move the field, no electrons will move. A flow of current requires a constant relative motion of the magnetic field and the inductor.

The induction is not just lightning a bulb it is used in devices like transformer to step up or step down the voltage

## 1. What is "Electron Flow Creates Magnetic Field Around Coil with Permanent Magnet"?

"Electron Flow Creates Magnetic Field Around Coil with Permanent Magnet" is a phenomenon where the movement of electrons through a coil of wire creates a magnetic field around the coil, which can then interact with a permanent magnet to create motion or generate electricity.

## 2. How does electron flow create a magnetic field?

When an electric current flows through a wire, it creates a circular magnetic field around the wire. In a coil of wire, this magnetic field is intensified because the current is flowing through multiple loops, creating a stronger magnetic field around the entire coil.

## 3. What role does the permanent magnet play in this phenomenon?

The permanent magnet provides a source of magnetic field that can interact with the magnetic field created by the coil. This interaction can create motion or induce electricity in the coil.

## 4. What are the applications of this phenomenon?

This phenomenon has various applications in everyday life, such as in electric motors and generators. It is also used in medical imaging devices like MRI machines and in other industrial processes that require the conversion of electrical energy into motion or vice versa.

## 5. How can this phenomenon be controlled or manipulated?

The strength and direction of the magnetic field created by the coil can be controlled by adjusting the amount and direction of current flowing through the wire. Additionally, the strength and placement of the permanent magnet can also affect the overall magnetic field and the resulting motion or electricity generated.

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