What is an electromagnetic wave?
The term electromagnetic wave describes the way in which electromagnetic radiation (EMR) moves through the universe. Different forms of EMR are characterized by their wavelengths, which differ from many yards (meters) to a distance less than the diameter of the atomic core. The entire range, in the declining order of the wavelength, passes from the radio waves through microwaves, visible light, ultraviolet and X -rays to gamma rays and is known as an electromagnetic spectrum. Electromagnetic waves have many applications, both in science and in everyday life.
In many ways, an electromagnetic wave behaves similarly to the wave on the water or a sound on a journey through the medium, such as air. For example, if there is a light on the screen with a barrier with two narrow slots, you can see a pattern of light and dark stripes. This is called the interference formula: where the ridges of the waves from one slot meet with the other, strengthen each other and create a bright stripe, but, where the ridge meets the trough, cancels and leaves a dark strip. Lightcan also bend around an obstacle, such as the ocean circuit breaker around the port wall: this is called diffraction. These phenomena provide evidence of the wave nature of light.
It has long been assumed that, like sound, light must pass through some medium. This was given by the name "Ether", sometimes written "aether", and was considered an invisible material that filled the space, but through which fixed objects could pass unlimited. Experiments designed to detect the ether of its effect on the speed of light in different directions did not find any evidence for him, and the idea was eventually rejected. Obviously, light and other forms of EMR did not require any medium and could travel through empty space.
wavelength and frequency
Like the ocean wave, the electromagnetic wave has a top of the trough. Wavelength is the distance between two identical wool points from cycle to cycle, such as the distance between onem by the top or ridge and others. EMR can also be defined in terms of its frequency, which is the number of ridges that pass in a given time interval. All EMR forms travel at the same speed: speed of light. The frequency therefore depends on the wavelength: the shorter the wavelength, the higher the frequency.
energy
shorter wavelength or higher frequency carries EMR more energy than longer wavelengths or lower frequencies. The energy carried by an electromagnetic wave determines how it affects. Low -frequency radio waves slightly disrupt atoms and molecules, while microwaves cause to move intensely: the material heats up. X -rays and gamma rays are packed with much more strike: they can break chemical bonds and knock electrons from atoms and create ions. For this reason, they are described as ionizing radiation.
origin of electromagnetic waves
The relationship between light and electromagnetism was created by the work of James Clerk Maxwell in the 19th century. That inDlo to study electrodynamics in which electromagnetic waves, such as light, are considered to be faults or "waves" in an electromagnetic field created by the movement of electrically charged particles. Unlike the non -existent Ether, the electromagnetic field is simply a sphere of influence of charged particles, not a tangible material thing.
Later work, at the beginning of the 20th century, showed that EMR also has properties of similar particles. The particles that make up electromagnetic radiation are called photons . Although it seems contradictory, EMR can act like waves or as a particle, depending on the type of experiment. This is known as the duality of the wave particle. It is also applied to subatomical particles, whole atoms and even survive large molecules that can sometimes behave like waves.
Duality of wave particles appeared as a quantum theory. According to this theory, the "wave" represents the probability of finding a particle, such as a photon, at a given place. Wave nature of particles andThe nature of the waves of similar particles led to a large number of scientific debate and some stunning thoughts, but overall there is an overall agreement of what it actually means.
In quantum theory, electromagnetic radiation is formed when subatomical particles release energy. For example, an electron in the atom can absorb energy, but must eventually drop to lower energy levels and release energy as EMR. Depending on how observed, this radiation may occur as a particle or electromagnetic wave.
uses
Many modern technologies depend on electromagnetic waves. Radio, television, mobile phones and the Internet rely on the transmission of IO EMR radfreques through air, space or optical fiber cables. Lasers used to record and play DVDs and audio CDs use light waves to write and read from discs. X -ray machines are an essential tool in medicine and airport security. In science our knowledge of the universe comes from velKé parts of light analysis, radio waves and X -rays from distant stars and galaxies.
Danger
It is not that the electromagnetic waves of low energy such as radio waves are harmful. In higher energies, however, EMR poses risks. Ionizing radiation, such as X -rays and gamma rays, can kill or damage living cells. They can also change DNA that can lead to cancer. The risk to patients from medical X-rays is considered negligible, but radiographs who are regularly exposed to them wear lead aprons-X-ray rays cannot penetrate-they have been protected. Ultraviolet light, present in the sun, can cause burning and can also cause skin cancer if the exposure is excessive.