# How does the wire know the magnetic flux has changed?

• Loniuc
In summary, when a metal wire is exposed to a changing magnetic field, it reacts by creating an induced current. This phenomenon is possible because the changing magnetic field induces an electric field, which drives the current in the wire. This eliminates the need for the wire to have a memory of the previous magnetic field flux, as it simply responds to the presence of the electric field. This explanation solves the "memory problem" and provides a clear understanding of the process.
Loniuc
If we have a metal wire and a magnetic field "inside" it, when the flux of the magnetic field changes, then the wire "reacts" by "creating" an induced current.

After learning this law, it eventually came to my mind the question: how does the wire know that the magnetic field flux has changed? I mean, in order to note the change, the wire somehow needs to have memory: "the magnetic field flux was x one second ago, and now it's x+dx... ok, it's time to induce a current".

Inanimate objects, such as wires, i.m.o. only know what happens around them instantly, so i find very hard to understand the fact that an inanimate object can detect a change of a physical variables in two different moments.

Good thinking. There must be something going on at the wire to "tell" it to induce a current. And there is. The changing magnetic field induces a surrounding electric field--it's that electric field which drives the current.

Ok, that makes much more sense. The change in the magnetic flux induces an electrical field, so the wire does not need to pay any attention to anything but to the existence (or not) of an electric field. This way the "memory problem" is solved: once there is an electric field (and the wire does not mind about its origin at all), the wire says: "hey, what's up? an electric field is present: ok electrons, it's time to woark: moving on...".

## 1. How does the wire detect changes in magnetic flux?

The wire is made up of conductive material, typically copper or aluminum, which allows electrons to flow through it easily. When a magnetic field changes, it induces a current in the wire due to the movement of these electrons. This change in current can be measured and detected by instruments.

## 2. What role does the wire play in detecting magnetic flux changes?

The wire acts as a sensor for changes in magnetic flux. Its conductive properties allow it to detect and respond to the changes in the magnetic field. Without the wire, it would be difficult to measure or observe changes in magnetic flux.

## 3. How does the wire convert magnetic flux changes into electrical signals?

As mentioned before, the wire's conductive properties allow it to respond to changes in magnetic flux by inducing a current. This current can then be measured and converted into electrical signals that can be interpreted and analyzed.

## 4. Is the wire the only way to detect changes in magnetic flux?

No, there are other methods and devices that can be used to detect changes in magnetic flux, such as magnetic field sensors or Hall effect sensors. However, the wire is a commonly used and effective means of detecting these changes.

## 5. Can the wire be influenced by external factors, affecting its ability to detect changes in magnetic flux?

Yes, the wire's ability to detect changes in magnetic flux can be affected by external factors such as temperature, external magnetic fields, and the quality of the wire itself. These factors should be taken into account when conducting experiments or using the wire as a sensor.

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