Electromagnetic field

November 2, 2021

The Electromagnetic Field is one of the most important aspects in science, so we must know it in depth. It is for this reason that we must know everything related to this.

Origin of the Electromagnetic Field

To begin we must know more about an Electromagnetic Field (EMF). We must know that electric fields owe their origin in voltages. In this case, the higher the voltage, the stronger the field. At the same time we must understand that magnetic fields are generated from electric currents. In this case when a current is stronger, the resulting field is much stronger.

However in the latter case the electric field can exist even when there is no current. When there is current, the magnitude of the magnetic field will change with power consumption. However, the strength of the electric field will remain the same.

The Electromagnetic Field comes from natural sources, in fact in our environment we can find Electromagnetic Fields everywhere. Although these cannot be seen with the naked eye, they are still present.

Specifically, we can say that they are produced by the accumulation of electrical charges in certain areas of the atmosphere as a result of the storm. We must bear in mind that the Earth’s magnetic field causes the orientation of the compass needles in a North-South direction.

Another origin of Electromagnetic Fields is that generated by man. A clear example is X-rays, where the electricity that arises from any current has associated Electromagnetic Fields, but of a low frequency.

Similarly, there are different types of radio waves with a higher frequency that is used to transmit information. This can be through television antennas, radio stations or mobile phone bases, in both cases electromagnetic fields are generated.

What are Electromagnetic Fields?

When we speak of an Electromagnetic Field or electromagnetic radiation as it is also known, we refer to the combination of waves. Which propagate through space transporting tiny packets of energy known as photons from one place to another.

Specifically, we can say that electromagnetic fields are a combination of an electric field and a magnetic field. From both, certain electrical and magnetic effects are caused, which has an effect of attraction and repulsion in a space.

Field Types

An important point that we must know about electromagnetic fields is that they have different types. This like the other remnants of electromagnetic waves, can be divided into several subclasses based on their physical characteristics of frequency and wavelength. In specific we can say the different CEM are;

Static electric fields

These are those that originate from the presence of electrical charges, without the need for a current. We must bear in mind that every charge generates an electric field (E) around it. Being E a vector magnitude so it will have a numerical value, a direction and a sense. Although it is important to note that static fields do not vary over time.

Extremely Low Frequency Fields (ELF)

In this case, as its name indicates, they are fields that are found at a frequency of 3 Hz to 3 kHz. It is important to mention that the most common sources of this type of field are electrical distribution networks and electrical appliances that usually operate at 50 Hz.

High frequency fields

Another of the electromagnetic fields are those of high frequency, which have a frequency that ranges from 300 MHz to 300 GHz . In this case we find several examples, such as microwave ovens or speed cameras.

Radio frequency fields

In this case we are talking about a variable CEM, which has a frequency interval between 3 kHz and 300 MHz. To mention some examples of these fields, we have induction cookers, modulated broadcasting antennas or arc welding equipment.

Static magnetic fields

Represented by the letter H, magnetic fields are produced by moving charges. Specifically, we can say that it is produced by electric currents or by permanent magnets. We must mention that magnetic fields have a vector magnitude.

To all this we must add that magnetic fields can appear with another vector magnitude. In summary we can say that static magnetic fields are created by permanent magnets. But also by electricity circulating as a direct current.

Why are Electromagnetic Fields so different?

As we have seen, the Electromagnetic Field has a wide variety of types. We must bear in mind that one of the main magnitudes that characterize an electromagnetic field is its frequency . As well as the corresponding wavelength.

Specifically, we can say that the effect on the body of the different electromagnetic fields is a function of their frequency. What we must do to understand all this we must imagine electromagnetic waves as a series of very uniform waves. Which move at a great speed (the speed of light for example).

When we talk about frequency we are simply talking about a description of the number of oscillations or cycles per second. On the other hand, when we talk about a wavelength , we refer to the distance between one wave and the next.

In this sense we can say that therefore the wavelength and frequency are closely linked to each other. Keep in mind that when the frequency is higher, the wavelengths will be much shorter.

How to measure the Electromagnetic Field?

Non-ionizing electromagnetic fields and ionizing radiation

Other important concepts to understand about an Electromagnetic Field is that electromagnetic waves are transported by particles called quanta of light. In general, the light quanta of waves with higher frequency carry much more energy. It is the opposite when it comes to lower frequency waves. It is important to note that in the former the wavelengths are shorter, but in the latter the wavelengths are longer.

However, we must bear in mind that some electromagnetic waves carry so much energy in terms of light. Which are capable of breaking the bonds of molecules. If we talk about the radiation that makes up the electromagnetic spectrum, the gamma rays emitted by radioactive materials, cosmic rays and X-rays, we can say that it has the aforementioned capacity, but they are known as ionizing radiation.

On the other hand, we must mention that non-ionizing radiation is one that is composed of quanta of light without enough energy to break molecular bonds. Among the sources that generate man-made electromagnetic fields, we find that these are at the extreme end of the electromagnetic spectrum. Corresponding to relatively long wavelengths. Which have low frequencies and have quanta that are not capable of breaking chemical bonds.

Where is the Electromagnetic Field used in everyday life?

As we must already know, the Electromagnetic Field is the result of the combination of an electric field with a magnetic one. It is from this process that what we know as electromagnetic is generated. This phenomenon can be found in our daily life, some examples would be;

Electric guitar

Although they must know a lot about it, what few know is that it needs electricity through magnetic fields. Being in this way that the timbres of the strings are generated .


One of the clearest examples where the Electromagnetic Field is applied is in compasses, which would not work without it. They have a very simple structure and execution, since basically the movement of the needles is based on the magnetic principle of the poles . But also in electric ones, due to the interaction of mechanisms and friction that it generates.


As many must already know, a transformer is a device that increases or reduces the flow of energy . Basing its operation on the Electromagnetic Fields. Specifically, we can say that its operation is given by coils in an iron frame through which energy circulates.


Something that many do not know about the doorbells is that they work with electromagnetism. Both its operation and its design are formed by an electric current, which travels through an electromagnet . Which then moves a small hammer that interrupts the current, which generates the sound of the bell.

Electric motor

The latest example of an Electromagnetic Field in everyday objects is the electric motor. To begin we must say that its function is to transform energy into movement, something that it does thanks to two fundamental parts within the engine. These two parts are the rotor that is composed of several coils and the stator which is a magnet that can be found in the coils.

With this in mind we can say that the resulting energy is generated by the friction of both parts when rotating the rotor. It is important to mention that when this happens an alternating current of energy is generated .

Dr. Loony Davis5
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Born and raised in Brussels in an English family, I have always lived in a multicultural environment. After several work experiences in marketing and communication, I came to Smart Water Magazine, which I describe as the most exciting challenge of my career.
I am a person with great restlessness and curiosity to learn, discover what I do not know, as well as reinvent myself daily, someone who is curious about life and wants to know. I enjoy sharing knowledge.
This is my personal project but I also collaborate in other blogs, it is the case, the most important web on water currently exists in the US, if you are interested you can read my articles here.

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