Radiation has an important characteristic, that is, it is "reciprocal". Regardless of the temperature of the object (gas) are radiated outward, the object A can be radiated to the object B, at the same time B can also be radiated to A. This is different from conduction. This is different from conduction, which is unidirectional.
Radiation energy is absorbed by the body when the thermal effect occurs, the object absorbs different radiation energy, the resulting temperature is different. Therefore, radiation is an important way to convert energy into heat.
Radiation is in the form of electromagnetic waves outward dispersion. It is spreading energy in the form of fluctuations. Radio waves and light waves are electromagnetic waves. They travel very fast, the same speed as light waves (3 x 1010 cm/sec) in a vacuum and a little slower in air.
Electromagnetic waves are synthetic waves composed of waves of different wavelengths. Its wavelength ranges from cosmic rays of 10E-10 microns (1 micron = 10E-4 cm) to radio waves with wavelengths up to several kilometers.Υ rays, X-rays, ultraviolet, visible light, infrared, ultra-shortwave and long-wave radio waves all belong to the range of electromagnetic waves. What is visible to the naked eye is a very short section of electromagnetic waves, from 0.4-0.76 micrometers this part is called visible light. Visible light by the prism after spectroscopy, become a band of red, orange, yellow, green, cyan, blue, purple seven colors, which is called the light band spectrum. The longest wavelength of red light, violet wavelength is the shortest, the wavelength of the other colors of light is in between. Wavelength longer than red light (& gt; 0.76 microns) have infrared radio waves; wavelength shorter than the violet light (& lt; 0.4 microns) have ultraviolet, Υ rays, X-rays and so on. Although these radiations are invisible to the naked eye, they can be measured by instruments.
The wavelength of solar radiation is mainly 0.15-4 microns, of which the maximum wavelength of radiation is 0.5 microns on average; the wavelength of terrestrial and atmospheric radiation is mainly 3-120 microns, of which the maximum wavelength of radiation is 10 microns on average. It is customary to call the former short-wave radiation and the latter long-wave radiation
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References:< Computer mainframes, monitors, mice, keyboards, and related equipment around the computer produce radiation that the eye cannot see and the hand According to scientific research: computer-generated low-frequency electromagnetic radiation on the human body caused by the harm is hidden, accumulated, people often (long-term) in the ultra-intense computer low-frequency electromagnetic radiation environment using computers, resulting in dizziness, headache, brain swelling, tinnitus, insomnia, dry eyes, vision loss, loss of appetite, fatigue and weakness, memory loss, part of the people hair loss, leukocytosis, immunity to the bottom of the cataracts, leukemia, brain cancer, breast cancer, blood vessel dilation, blood pressure abnormalities, chest tightness, bradycardia, decreased heart blood flow, sinus arrhythmia, reduced sperm quality in men, some women's menstrual disorders, miscarriage in pregnant women, stillbirths, fetal malformations, reproductive pathologies, hereditary pathologies, cancers, and other terrible diseases. After operating the computer, the face will be adsorbed many electromagnetic radiation particles, often by the radiation will appear face rash. A person continuously operating computer work for five hours, the computer generated by low-frequency radiation damage to the human body, equivalent to a day of loss of life. The more the number of computers in the room, the more densely placed, the greater the amount of low-frequency electromagnetic radiation in the air, the greater the harm to the human body. Computer monitor (screen) of the northern radiation intensity greatly exceeds the monitor (screen) front radiation intensity. Some enterprises and institutions using computers at work, school computer classrooms and some Internet cafes before and after, left and right close horizontal rows of computers, the front row of people back against the back row of computer monitors, before and after, left and right near neighboring computers, by the greater harm. Even if the monitor hangs a general "radiation protection net (plate)" can only block a small part of the radiation from the front of the monitor. Can not solve the fundamental problem. Many people mistakenly believe that as long as the "liquid crystal display" to replace the computer on the "ordinary" (glass) monitor, you can completely eliminate the computer host, monitor, mouse, keyboard and related equipment around all the radiation. In fact, it is simply not possible to eliminate all the radiation in all parts of the computer machine, but only a high investment to reduce the "monitor" on the local radiation, but still can not eliminate the computer main, mouse, keyboard and related equipment around the computer radiation as usual hurt the problem. Reducing the harm of computer radiation measures Computer radiation which everyone knows, but radiation in the end, in the end, in the end, how much harm? The computer generated rays including visible light, radio waves, low-frequency electromagnetic waves, static electricity and ultrasound. According to the radiation status is divided into free radiation and non-free radiation: free radiation from the tube; non-free radiation from the computer monitor electronic parts of the current, voltage. But no matter what kind of radiation, in general, under normal operating conditions, its intensity is not enough to harm the human body.