How much electromagnetic radiation is around us?

When the induction cooker works, the radiation actually reaches more than 400 mG, which is the largest radiation among all kinds of electrical appliances. It was not until two meters away from the induction cooker that the electromagnetic radiation dropped below 2mG.

The microwave oven ranks second, and the radiation reaches 130-360 mg, 1.5 m before it drops below 2mG.

The third kind of electrical appliance with electromagnetic radiation is the hair dryer that ladies often use, and the radiation energy can reach 80mG.

In addition, the electromagnetic radiation of air conditioner is 50mG, electric shaver 19mG, rice cooker 15mG, washing machine 12mG and refrigerator 10mG. The radiation of TV, CRT TV and LCD TV commonly used in people's homes is very different. The front radiation of a 25-inch CRT TV reaches 20mG, and the radiation energy beyond half a meter drops below 2mG, while the radiation of an LCD TV is only 1.3mG.

2, office radiation, the back of the computer is greater than the front.

In addition to life, we also encounter electromagnetic radiation at work.

According to the instrument measurement, the radiation of the display surface of a 17 inch kinescope is 6mG, and the radiation will drop below 2mG when the distance is 10cm. In other words, as long as people sit correctly when using the computer, their forearms will naturally straighten, and their bodies will be free from harmful radiation.

However, the radiation on the back of CRT monitor is much larger than that on the front, which is 20mG, and so is the computer host, which is 1mG on the front and 20mG on the back. 20 mg of electromagnetic radiation can only be reduced to 2 mg when it is about 30cm. Liquid crystal display does not have the above problems, and its electromagnetic radiation is about 2mG, regardless of positive or negative. In addition, the electromagnetic radiation of photocopiers and printers is 3-6 mg.

3, electrical radiation ranking

Through instrument measurement, the radiation values of various electrical appliances are obtained and listed in turn for your reference.

Induction cooker (400 mg), microwave oven (130-360 mg), mobile phone (2-2-100 mg), hair dryer (80 mg), air conditioner (50 mg), kinescope display (6-20 mg), computer host (/kloc-

Extended data:

Electromagnetic radiation, also known as e-cigarette, is composed of electric energy and magnetic energy transmitted in space, and this energy is produced by charge movement. For example, moving charges from a radio frequency antenna transmitting signals will generate electromagnetic energy. The electromagnetic "spectrum" includes all kinds of electromagnetic radiation, from extremely low frequency electromagnetic radiation to extremely high frequency electromagnetic radiation.

There are also radio waves, microwaves, infrared rays, visible light and ultraviolet rays between them. The radio frequency part of the electromagnetic spectrum is generally defined as radiation with a frequency of about 3 khz to 300 GHz. Some electromagnetic radiation has certain influence on human body.

Electromagnetic radiation is the phenomenon of electromagnetic wave emission or leakage into the air caused by the interactive change of electric field and magnetic field. Electromagnetic radiation is an invisible and intangible field. The earth where human beings live is itself a big magnetic field. Both thermal radiation and lightning on its surface can produce electromagnetic radiation, and the sun and other planets also constantly produce electromagnetic radiation from outer space.

Natural magnetic field, sunlight, household appliances, etc. Different intensities of radiation will be emitted around human beings. Electromagnetic radiation is the external manifestation that atoms and molecules in matter are in motion.

What is the form of electromagnetic radiation (sometimes called EMR)? Self-propagating waves in vacuum or matter. Electromagnetic radiation has oscillations of electric field and magnetic field components, which propagate energy in two mutually perpendicular directions. Electromagnetic radiation is divided into different types according to frequency or wavelength. These types include (in order of increasing frequency): electric power, radio waves, microwaves, terahertz radiation, infrared radiation, visible light, ultraviolet rays, X-rays and gamma rays.

Among them, the wavelength of radio waves is the longest and the wavelength of gamma rays is the shortest. X-ray and γ -ray have strong ionization ability, while other electromagnetic radiation has relatively weak ionization ability, while those with lower frequency have no ionization ability.

Wavelength and frequency determine another characteristic of electromagnetic field: electromagnetic waves are carried by small particles and photons. Photons of high frequency (short wavelength) electromagnetic waves will carry more energy than photons of low frequency (long wavelength) electromagnetic waves. Some electromagnetic waves can carry so much energy per photon that it has the ability to break the chemical bonds between molecules.

In the electromagnetic spectrum, gamma rays, cosmic rays and X rays produced by radioactive substances all have this characteristic, which is called "ionizing radiation". The electromagnetic field with insufficient photon energy to break the chemical bonds of molecules is called "non-ionizing radiation". Some artificial sources of electromagnetic fields constitute an important part of our modern life, such as electricity (power transmission and transformation, household appliances, etc.). ), microwave (microwave oven, microwave signal tower, etc. ) and radio waves (mobile phones, mobile communications, radio and television towers, etc. ).

At the end of the electromagnetic spectrum with relatively long wavelength and relatively low frequency, their photons have no ability to break chemical bonds. Therefore, this kind of electromagnetic wave is a non-ionizing electromagnetic field, and its impact on human body is immediate, similar to sound wave, while the impact of ionization on human body is cumulative.

The energy generated by electromagnetic radiation depends on frequency and intensity. Generally speaking, the higher the frequency, the greater the intensity and the greater the electromagnetic radiation. X-rays and gamma rays with extremely high frequency can generate huge energy and destroy the molecules that make up human tissues. In fact, X-rays and gamma rays are powerful enough to ionize atoms and molecules, so they are classified as "ionizing" radiation.

Although both of these rays have medical uses, excessive exposure will do harm to health. The electromagnetic energy generated by X-rays and gamma rays is different from that generated by RF transmitter. The electromagnetic energy of RF devices belongs to the lower frequency end of the spectrum and cannot break the chemical bonds that bind molecules together, so it is classified as "non-ionizing" radiation.

Electromagnetic radiation comes from many sources. Both inside and outside the human body are covered with electric energy and magnetic energy from natural and artificial radiation sources; Lightning is an example of a natural radiation source. As for artificial radiation sources, they include microwave ovens, radios, TV broadcast transmitters and satellite communication equipment.

Electromagnetic radiation is divided into two levels: power frequency band radiation and radio frequency electromagnetic waves. The national standard electric field intensity of power frequency band is 4000v/m, and the magnetic induction intensity is 0.1mt; ; The unit of radio frequency electromagnetic wave is μW/㎝2, the national standard limit is 40, and the value of general public EIA is 20%.

Reference link: Baidu Encyclopedia-Electromagnetic Radiation