What are electromagnetic waves?

Aurymarie Cerdá Claudio

To know what an electromagnetic wave is, it is necessary to understand and internalize what is an electric field and what is a magnetic field. An electric field is going to be found wherever a charged particle is present; it is a property of this particle. It is the space surrounding the charged particle and it exerts a force on any other charged particle near it. A magnetic field is the space surrounding magnetic materials, and they are detected by the force they exert on other materials, that can interact with them; because if the other material does not has electric charges or particles then nothing could happened.

There are two basic types of charges: positive and negative charges. An atom contains both, protons and electrons which are positive charges and negative charges respectively. Protons and electrons interact with each other and cause the nucleus of that atom to situate in a specific position. If in an atom there were only protons then the nucleus will be always moving, because they interact between them but there is no force to counteract these forces. So it could be raised that like charges repel each other while unlike charges attract each other. A proton and an electron do not “touch” each other they interact because they are electric charged particles so they have both electric fields that are what makes them to interact. Electric charges exert forces to other electric charged particles through electric fields; the same thing happens with the magnetic fields. A magnet has a magnetic field that would interact with another magnetic material near the first one.

The interaction between a magnetic field and an electric field can be explained as follows. When having a flow of electrons each negatively charged particle will produce and electric field. Many electrons moving will then produce many electric fields. Each electric field will produce a magnetic field; of course magnetic materials will be present at this system. The interaction occurs as a consequence of the interaction at elementary particles level.

To explain what an electromagnetic wave is, using a radio antenna would help. When a current of electrons travels along the wire of this antenna an electric field is produced at the antenna. This electric field at the same time produces a magnetic field, that magnetic field creates a new electric field and so on. For this to happen, the first electric field needs to be changing so it can be produced. In this way the electric fields and the magnetic fields are connected to each other; the electric and magnetic fields oscillate and propagate through space forming the electromagnetic wave. The magnetic field and the electric field are considered a phase because they are a repetitive pattern that oscillates perpendicular to each other and they are perpendicular to the energy propagation. The frequency of the oscillations of the electric and magnetic fields the wavelength of the waves determines whether the electromagnetic wave is visible light, ultraviolet light, infrared light, radio waves, X-rays, or gamma rays; known as electromagnetic waves.