What waves are included in electromagnetic waves

Q1: What is electromagnetic wave? How many types of electromagnetic waves are there? Does it have any effect on the human body?

From a scientific point of view, electromagnetic waves are a type of energy, and any object that can release energy will emit electromagnetic waves. Electricity and magnetism can be said to be two sides of the same coin, and changing electricity produces magnetism, and changing magnetism produces electricity. Electromagnetic fluctuations are like water waves caused by a breeze blowing on the surface of the water, so they are called electromagnetic waves, and the number of times they change per second is the frequency.

When the frequency of electromagnetic waves is low, they can be transmitted mainly through tangible conductors; When the frequency increases, the electromagnetic wave will spill out of the conductor and transfer energy outward without the need for a medium, which is a kind of radiation. For example, the distance between the sun and the earth is very long, but when we are outdoors, we can still feel the light and heat of the sun, just like the principle of electromagnetic radiation that transmits energy through the phenomenon of radiation.

Electromagnetic radiation is a way of transferring energy, and the types of radiation can be divided into three types:

1.Ionizing radiation.

2.Non-ionizing radiation with thermal effects.

3.Non-ionizing radiation with no thermal effect.

The energy of an electromagnetic wave is directly proportional to its frequency. When high-energy electromagnetic waves transmit energy to other substances, it is possible to knock out the electrons of atoms and molecules in the substance, filling the matter with charged ions, and this effect is called"Free"The electromagnetic waves that cause this ionization phenomenon are called ionizing radiation, including gamma rays, X-rays, ultraviolet rays, etc.

Electromagnetic waves and infrared rays that enter the visible frequency cannot cause ionizing effect, which is called non-ionizing radiation. It is necessary to clarify the concept here, radiation injury refers to ionizing radiation (ionizing radiation will rob the body of the matter for electric charge, produce ions and destroy physiological tissues), non-ionizing radiation does not have the ability to ionize, will not produce free ions harmful to the human body, a large number of non-ionizing electromagnetic waves will only cause a warming effect.

This is like sunbathing or standing under a light bulb, as long as too much energy is not transmitted to the human body in a short period of time, the physiological tissues can be regulated, so long-term exposure to non-free electromagnetic waves within a safe range will not cause cumulative damage. Q2: Are we exposed to electromagnetic waves in our daily lives?

The environment in which we live"Electricity"with"Magnetic"In addition to the sunlight and lightning of nature, all kinds of electrical appliances, such as televisions, microwave ovens, light bulbs, computers, and even radio stations, television stations, amateur radio stations, radio taxis, police radio stations or satellite mobile communications, etc., all exist in our living environment.

Electromagnetic waves from the wavelength of the wave include radio waves, microwaves, infrared, visible light, ultraviolet rays, X-rays and gamma rays.

Electromagnetic waves include radio waves and magnetic waves.

Electromagnetic waves are actually divided into radio waves and magnetic waves, which are the general term for the two, but because electric fields and magnetic fields always appear at the same time, disappear at the same time, and convert into each other, they are usually called electromagnetic waves, and sometimes they can be directly referred to as radio waves.

Electromagnetic waves are electric and magnetic fields that oscillate the same and perpendicular to each other in space in the form of waves, and their propagation direction is perpendicular to the electric field, and the electromagnetic wave has a fixed rate in a vacuum, and the speed is the speed of light.

Basic properties of electromagnetic waves:

Electromagnetic waves have three major attributes, namely amplitude (intensity, light and sail strength), frequency (wavelength) and waveform (spectrum distribution), and for visible light, these three correspond to the brightness, hue and chromaticity of the light and face respectively.

For a single frequency of electromagnetic waves, there is also the concept of primary phase, the waveform is a sinusoidal curve (cosine curve), called a sine wave (cosine wave), the closer the waveform of the electromagnetic wave is to the sine wave, the purer its spectrum, the better the monochromaticity, a typical example is the laser.

An important property of electromagnetic waves is frequency, which can determine the various properties of electromagnetic waves, but to describe the frequency of electromagnetic waves, it is not necessary to use the frequency itself, but also to be a physical quantity related to frequency, commonly used wavelength, photon energy (proportional to frequency), wave number (the reciprocal of wavelength, proportional to frequency, default to the wavelength in a vacuum) and period (inversely proportional to frequency) and so on. <>