Magnetic fields and magnetic field induction
Magnetism is familiar to people from ancient times. The first written mention of it dates back to the I century BC. e., but scientists believe that knowledge about this phenomenon appeared much earlier. It is global and life without it on our planet is impossible at all. Therefore, researchers at all times tried to study this force and curb it for the progress of mankind.
A magnetic field
Living on Earth, without noticing it, we are constantly under the influence of various forces. The magnetic field is also no exception to this rule. Although, to be precise, it is defined as a special kind of matter, and not force. The source of its occurrence is charged electric particles or magnets. If we take the spatial characteristic of this matter, then it is a combination of forces capable of acting on bodies that are magnetized. This ability arises from the movement of discharges between the molecules of an object.The main condition for the emergence of such a field is a constant movement of electric charges. The interaction of magnetic and electric fields has led to the fact that they cannot exist separately. This phenomenon is called an electromagnetic field. All elements of such matter are inextricably linked and act so that their properties change.
Properties of magnetism
The magnetic field, like any other physical phenomenon on Earth, has its own characteristics:
- The origin is moving electrical charges.
- Induction of a magnetic field is its main force characteristic, which exists in each of its individual points and is directional.
- Its influence is limited to magnets, moving charges and current conductors.
- It is divided by scientists into two types: constant and variable.
- A person without special devices cannot feel the impact of magnetism.
- This is an electrodynamic phenomenon, because its source of origin is moving particles of electric current. And only the same particles can be affected by the magnetic field.
- The trajectory of the movement of charged particles can only be perpendicular.
Induction in magnetism
The induction of the magnetic field is determined by its directionality, that is, it is a vector and is inherent in any field that occurs in such conditions. It is always directed in the same way as the arrow, which rotates freely in the compass. Such a field is completely characterized by magnetic induction. Each point is the carrier of the direction and modulus of this force. If they are the same for all points of this field, then it is called homogeneous. The induction of a magnetic field in physics is denoted by a vector and a capital Latin letter B.
Magnetic induction formula
In order to calculate this power characteristic, you need to know the formula for its calculation:
- B = F: I x l.
In this formula:
B means magnetic field induction;
F is the force that acts on the conductor from the field;
I - the force with which the current passes through the conductor;
l is the actual length of the conductor itself.
The unit of induction, according to the International System of Units, is Tesla (T).
Lines passing in a magnetic field
Magnetic induction has a vector, that is, directivity. If it is displayed on paper, it will be expressed in lines.They coincide with tangents that have the same direction as the induction vector. If the magnetic field is uniform, then these lines run parallel to each other. When it is not homogeneous, the direction of this force will be different at all points of the arising field, and the tangents to them will look like circles.
The magnetic field can be created by various objects, for example, a solenoid. The solenoid, in its essence, is an electromagnet, that is, an inductance coil. To create a solenoid, a cylindrical surface (core) and an insulated live conductor (wire), which is wound onto the core, is required. The current passing through the wire creates this kind of matter around the solenoid. At this moment it turns into a magnet. If you turn off the electricity, all the special properties of the solenoid disappear, and when you turn it back on, they are renewed again. The more reason is wound around the core and the more current is supplied, the stronger the attractiveness of the solenoid will be.
Magnetic induction solenoid
Very interesting to consider is the solenoid, the length of which is much greater than its diameter.Induction of the magnetic field of the solenoid in this case everywhere has one directivity that is parallel to the core of the coil, which means that each line of the field is parallel to each other. If the conductor is wound evenly, then not only the direction is the same, but the numerical value will also be the same. Due to the fact that the solenoid has a very simple structure, its field was recognized as the field standard.
There are millions of magnets of different size and origin on our planet, but the largest of them, to which we constantly touch, is our Earth itself. The first time about the Earth as a similar subject was said in 1600. This year was marked by the appearance of the book of the English physicist William Hilbert, in which he closely links the Earth and this matter. In addition, he says that the axis of the Earth’s magnetic field and the axis along which the planet rotates are not identical, but, on the contrary, have only one point of contact. If you make a graphic drawing of this phenomenon around our blue ball, it immediately becomes apparent that it is very similar with a regular permanent magnet.The first maps showing our planet from this side were drawn by E. Halley in 1702. How does the earth regenerate its special properties? It's pretty simple. As you know, in the depths of our planet there is a core. This is a huge ball of red-hot iron, which is an excellent conductor of current, that is, a charged core and gives powerful flows of particles. Due to this phenomenon, the Earth is surrounded by the magnetosphere, which protects it from negative influences from the depths of the cosmos, and even from our own sun. Induction of the Earth’s magnetic field is 0.5 · 10- 4T.
Changes in the Earth’s magnetosphere
After the discovery of the Earth’s magnetic field, many physics scientists decided to tackle this problem. In 1635, G. Hellibrand found out that this layer of the globe is in constant change. These changes are divided into two types: permanent and short-term. Permanent occur due to deposits of ore minerals, which give distortion due to its own strong energy flow. The culprit of the short-term changes is the so-called "solar wind". It is a stream of electrical particles that erupt from the surface of the sun.The interaction of these two phenomena leads to "magnetic storms." If such a storm is strong, it can even lead to loss of radio communication or uncertainty of the compass needle. One of the most beautiful effects of such storms is the Northern Lights, as the poles are particularly susceptible to their influence.
Thus, magnetism is present in the life of every person. It affects us, even though we don’t feel it. Due to this phenomenon, our planet is not exposed to negative influences from the outside, and we have the opportunity to observe the colorful colors of Aurora.