The electromagnetism is a force of the most important, since along with the gravitational, strong nuclear and weak nuclear is part of the fundamental forces of the universe, which are those that can not be explained in terms of more basic forces. This force affects only bodies charged with electricity, and is responsible for the chemical and physical transformations of atoms and molecules. Electromagnetism is present on a daily basis, both in natural and artificial phenomena.
What is electromagnetism
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When we talk about the term electromagnetism in physics, it refers to the conjunction of electrical and magnetic phenomena, as well as the interaction of both forces. This has an effect on liquids, gases and solids.
In nature, electromagnetism has a presence in phenomena such as radio waves from the Milky Way, infrared radiation from bodies at room temperature, light, ultraviolet radiation from the Sun, gamma radiation, the northern lights and australes, among others.
On the other hand, the application of electromagnetism in everyday life is diverse. Such is the case of the compass, whose needle movement is generated by the polar magnetic principles and the electric ones by the interaction of the mechanism and the friction that originates. The bell, the electric guitar, the electric motor, transformers, microwaves, pendrives, microphones, airplanes, digital cameras, cell phones, thermometers, plates, ultrasound machines, modems, tomographs, are some of the best known objects in which this phenomenon takes place and that, in practical applications, exemplifies what electromagnetism is.
What is the electromagnetic field
It is a physical sensory field in which electrical particles produced by electrically charged bodies or objects interact. In such a field, there is a quantity of electromagnetic energy. But to better understand the concept, it is important to understand how and why the electric field and the magnetic field are generated.
The electric field takes place when there are voltage differences and the higher the voltage, the greater the field. This, then, is the space where electrical forces act. Knowing the scope of the electric field will allow knowing the intensity level and what happens with a charge in a certain part of the field, regardless of not knowing what causes it.
For its part, the magnetic field originates from electric currents, and the greater the current, the greater the field. It is the agitation that the magnet produces in the region around it, how it affects it and in what direction. It is represented by field lines that go from the outside of the north pole to the south pole of the magnet, and inside from the south pole to the north pole. Said lines will never intersect, so they separate from each other and from the magnet, parallel and tangential to the direction of the field at the points.
What is the electromagnetic spectrum
It is the set of electromagnetic energies of the waves, that is to say, all the electromagnetic radiation ranging from those with a shorter wavelength (X-rays, gamma rays), ultraviolet radiation, light and infrared radiation, to those of greater length (radio waves).
The spectrum of an object or fluid will be the characteristic distribution of its electromagnetic radiation. There is a theory that the limit of the shortest wavelength is approximately the Planck length (a measure of subatomic length) and the upper limit of the long wavelength is the size of the universe itself, even though the spectrum is continuous and infinite.
Maxwell equations
James Maxwell managed to formulate the electromagnetic theory, encompassing electricity, magnetism and light as different expressions of the same phenomenon. This hypothesis developed by the physicist was called the Classical Theory of Electromagnetic Radiation.
Since ancient times, scientists and people observed with fascination electromagnetic phenomena, such as electrostatics, magnetism and other manifestations within this field, but it was not until the 19th century, when thanks to the work of different scientists, they were able to explain part of the pieces that made up the puzzle of electromagnetism as it is known today.
It was Maxwell who unified all of them in four equations: Gauss's Law, Gauss's Law for the magnetic field, Faraday's Law, and the generalized Ampère's Law, which helped define what electromagnetism is.
1. Gauss's Law: describes how charges affect the electric field and establishes that these charges are sources of electric field as long as they are positive, or sinks of it if they are negative. Hence, like charges tend to repel each other and different charges tend to attract each other. This law in the same way establishes that the electric field will weaken with distance under the inverse quadratic law (the intensity is inversely proportional to the square of the distance from the center of origin), and endowing it with geometric properties.
2. Gauss's Law of magnetism: states that neither sources nor sinks exist within the magnetic field, therefore, there are no magnetic charges. In the absence of sources and sinks, magnetic fields generated by objects must close in on themselves. That is why, if a magnet is divided in half, the magnetic field will close in the area where it was cut, so two magnets with two poles each will be created. This suggests that monopoles on earth would be impossible.
3. Faraday's Law: says that if a magnetic field changes over time, this will activate it by closing. If it increases, the electric field will be oriented in a clockwise direction, and if it decreases, it will be oriented in the opposite direction. It is then true that not only the charges and the magnets can influence the fields, but also each other, in both directions.
Within this law, electromagnetic induction is observed, which is the production of electric currents by magnetic fields that vary with time. This phenomenon produces electromotive force or voltage in a body exposed to a magnetic field and, as said object is conductive, the induced current is produced.
4. Ampère's Law: explains that an electric field with moving charges (electric current) activates the magnetic field by closing. Electric current is very useful, since with it artificial magnets can be created, by passing said element through a coil and, having a magnetic field, which causes that the greater the intensity of the current, the more the power will be amplified. magnetic field intensity. This type of magnet is called an electromagnet, and most of the magnetic fields on the planet are generated this way.
Branches of electromagnetism
To fully understand what electromagnetism is, one must understand the different manifestations in these electromagnetic phenomena: electrostatics, magnetostatics, electrodynamics and magnetism.
Electrostatics
Electrostatics refers to the study of electromagnetic phenomena that originate in electrically charged bodies (it has an excess - positive charge - or lack - negative charge - of electrons in the atoms that compose it) at rest.
It is known that if objects charged with electricity have excess electrons in the atoms that compose them, then they will have a positive charge, and they will have a negative charge when they are deficient.
These bodies exert forces on each other. When a charged object is subjected to a field belonging to another charged object, it will be subject to a force proportional to the magnitude of its charge and that of the field at its location. The polarity of the charge will decide whether the force will be attractive (when they are different) or repulsive (when they are the same). Electrostatics is useful for the study and observation of electrical storms.
The magnetism
It is the phenomenon by which bodies attract or repel each other depending on the type of charge they have. All the materials that exist will be more or less influenced according to their composition, but the only magnet in nature that is known is magnetite (which is a mineral composed of two iron oxides and has the property of attracting iron, steel and other bodies).
Magnets have two areas where the forces manifest themselves with greater magnitude, located at the ends and are called magnetic poles (north and south).
The fundamental property of the interaction between magnets is that their like poles repel each other, while the different ones attract. This is, because this effect is related to the magnetic field lines (from the north pole to the south), and when two opposites approach, the lines jump from one pole to the other (adhere), this effect will reduce as the distance between the two is greater; when two equal poles approach, the lines begin to compress towards the same pole, and if they are compressed, the lines expand, so that both magnets cannot approach and repel each other.
Electrodynamics
Study the electromagnetic phenomena of charged bodies in motion and fields, both electric and magnetic variables. Within it, there are three subdivisions: the classical, the relativistic and the quantum.
- The classic includes other effects, such as induction and electromagnetic radiation, magnetism and induction and electric motor.
- The relativist establishes that, having an observer moving from its reference frame, it will measure different electric and magnetic effects of the same phenomenon, since neither the electric field nor the magnetic induction behave as vector physical magnitudes.
- Quantum describes the interaction between bosons (particles that carry the interaction) and fermions (particles that carry matter), and is used to explain atomic structures and relationships between complex molecules.
Magnetostatics
It is the study of physical phenomena in which constant magnetic fields intervene in time, that is, they have been produced by stationary currents. This includes the attraction that the magnet and electromagnet have on iron and different metals. The phenomena produced in this area are characterized by the creation of a magnetic field around the magnetized body that loses intensity with distance.
What are electromagnetic waves
They are waves that do not need a material medium for their propagation, so they can travel through a vacuum and at a constant speed of 299,792 kilometers per second. Several examples of these types of waves are light, microwaves, X-rays, and television and radio transmissions.
The radiations of the electromagnetic spectrum present diffraction (deviation when obtaining an opaque object) and interference (superposition of waves), which are the typical properties of wave motion.
The application of electromagnetic waves has had a strong impact on the world of telecommunications by making wireless communication possible through radio waves.
What is electromagnetic radiation
It is the propagation of electric and magnetic particles oscillating, and where each one generates a field (electric and magnetic). This radiation causes waves that can propagate through air and vacuum: electromagnetic waves.
