It’s very simple. Radiation and radiation are different. The author will understand it when he thinks of a question - radioactive substances.

Oh, the radiation of radioactive materials is nothing more than gamma flow, alpha flow, beta flow, but the consequences of being exposed to uranium, iridium, plutonium and other radioactive materials are the consequences of being under a desk lamp... ...........

Additional information:

1. Y-rays are produced by radioactive isotopes such as 60Co or 137Cs. It is a high-energy electromagnetic wave with a very short wavelength (0.001-0.0001nm), strong penetrating power, and a long range. It can irradiate many materials at one time, and the dose is relatively uniform. It is highly dangerous and must be shielded (a few centimeters of lead plate or a few meters thick concrete walls).

2. X-rays are high-energy electromagnetic waves produced by x-ray machines. The wavelength is longer than gamma rays, the range is slightly shorter, and the penetrating power is not as good as gamma rays. There is a danger and should be shielded (a few millimeters of lead sheet).

3. Beta rays are negatively charged particles released when radioactive isotopes (such as 32P, 35S, etc.) decay. It has short range and weak penetration in the air. The ionization effect in living organisms is stronger than gamma rays and x-rays.

4. Neutron A stream of uncharged particles. The radiation source is a nuclear reactor, accelerator or neutron generator. When the atomic nucleus is bombarded by foreign particles, a nuclear reaction occurs and is released from the atomic nucleus.

Neutrons are divided into fast neutrons, slow neutrons and thermal neutrons according to their energy.

Neutron ionization density is high and often causes large mutations.

In current radiation breeding, thermal neutrons and fast neutrons are most commonly used.

5. Ultraviolet light is a kind of non-ionizing radiation with very weak penetrating power.

After absorbing ultraviolet light energy of a certain wavelength, nucleic acids enter an excited state, which enhances the activity of organic compounds and causes mutations. Can be used to treat microorganisms and plant pollen grains.

6. Laser is a new light source developed in the 1960s.

Laser is also an electromagnetic wave. The wavelength is longer and the energy is lower. Because of its good directionality, it is only 0.1. Left and right deviations, high brightness per unit area, and good monochromaticity can cause biological cells to undergo vibrational absorption, leading to energy state excitation of atoms and molecules or ionization of atoms and molecules, thereby causing internal variation within the organism.

Various rays have different biological effects due to different ionization densities, and the mutation rates they cause are also different. In order to obtain higher beneficial mutations, appropriate rays must be selected, but due to factors such as ray sources, equipment conditions, and safety, gamma rays and x-rays are currently most commonly used.

Just to add:

All objects in nature, as long as the temperature is above absolute zero, are constantly transmitting heat in the form of electromagnetic waves. This kind of transmitted energy The method is called radiation. The energy emitted by objects through radiation is called radiant energy. Radiation is calculated in terms of roentgen/hour (R)

Radiation has an important feature, that is, it is "reciprocal". Regardless of the temperature of the object (gas), it radiates outward. Object A can radiate to object B, and object B can also radiate to object A. This is different from conduction, which proceeds in one direction. Anyone who has been exposed to radiation should wash the entire body thoroughly with soap and plenty of water, and seek help from a doctor or expert immediately! (The picture shows the warning sign of "Dangerous Radioactive Materials, Beware of Radiation")

Radiation energy A thermal effect occurs when absorbed by an object. The radiant energy absorbed by the object is different, and the temperature generated is also different. Therefore, radiation is an important way of converting energy into heat. Radiant heat transfer is a process that relies on electromagnetic wave radiation to transfer heat between hot and cold objects. It is a non-contact heat transfer that can also be performed in a vacuum. The electromagnetic waves emitted by objects are theoretically distributed within the entire spectrum range, but within the temperature range encountered in industry, what is of practical significance is the thermal radiation with a wavelength between 0.38 and 1000 μm, and most of it is in the infrared (also known as infrared rays). (called heat rays) in the range of 0.76 to 20 μm. The so-called infrared heating uses the thermal radiation in this section. Studying the laws of thermal radiation is very important for the reasonable design of heat transfer in the furnace, and is also of positive significance for the labor protection of high-temperature furnace operators.

When a system needs to be insulated, even if the temperature of the system is not high, the influence of radiation heat transfer cannot be ignored. For example, the thermos bottle is plated with silver to reduce heat loss caused by radiation heat transfer. The basic concept of thermal radiation: While any object emits radiant energy, it also continuously absorbs radiant energy from surrounding objects. The difference between the energy radiated by an object and the energy absorbed is the net energy it delivers. The radiation ability of an object (that is, the energy radiated outward by a unit surface per unit time) increases rapidly as the temperature increases. Generally speaking, when an object receives radiation (energy Q) from other objects, the part that is absorbed and converted into heat energy is QA, the part that is reflected is QR, and the part that passes through the object is QD. Obviously these parts There is a relationship with the total energy as shown in the following formula: QA+QR+QD=Q If A=QA/Q is called the absorption rate, R=QR/Q is called the reflectivity, and D=QD/Q is called the penetration rate Transmittance, then: A+R+D=1

If the object’s A=1, R=D=0, that is, the energy of thermal radiation reaching the surface of the object is completely absorbed, the object is called It is an absolute black body, or black body for short. If R=1, A=D=0, that is, all the energy of thermal radiation reaching the surface of the object is reflected; when this reflection is regular, the object is called a mirror body; if it is random reflection, it is called an absolute white body. . If D=1, A=R=0, that is, all the energy of thermal radiation reaching the surface of the object passes through the object, and the object is called a heat transmitter. In fact, there are no absolute black bodies and absolute white bodies, only some objects are close to absolute black bodies or absolute white bodies. For example: the matte black paint surface is close to a black body, and its absorptivity is 0.97 to 0.98; the polished copper surface is close to a white body, and its reflectivity can reach 0.97. The main factors that affect the absorption and reflection properties of solid surfaces are surface condition and color. Surface condition often has a greater impact than color. Solids and liquids are generally impermeable to heat. The energy of thermal radiation only passes through a short distance after passing through the surface of a solid or liquid (generally less than 1 mm, and only passes through 1 μm after passing through a metal surface) before being completely absorbed. Gases have almost no ability to reflect thermal radiation energy. Monoatomic and symmetric diatomic gases (such as Ar, He, H2, N2, O2, etc.) at normal temperatures can be regarded as heat transmitters. Polyatomic gases (such as CO2, H2O, SO2, NH3, CH4, etc.) have considerable absorption capabilities within a specific wavelength range.

Radiation is emitted in the form of electromagnetic waves and particles (such as alpha particles, beta particles, etc.). Radio waves and light waves are both electromagnetic waves. They propagate very quickly, at the same speed as light waves (3×1010 cm/sec) in a vacuum and slightly 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 centimeters) to radio waves with wavelengths of several kilometers. Gamma rays, X-rays, ultraviolet rays, visible light, infrared rays, ultrashort wave 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 to 0.76 microns. This part is called visible light. After visible light is split by a prism, it becomes a light band composed of seven colors: red, orange, yellow, green, cyan, blue, and violet. This light band is called a spectrum. Among them, red light has the longest wavelength, violet light has the shortest wavelength, and the wavelengths of other colors of light are in between. Those with wavelengths longer than red light (>0.76 microns) include infrared rays and radio waves; those with wavelengths shorter than purple light (<0.4 microns) include ultraviolet rays, gamma rays, X-rays, etc. Although these radiations are invisible to the naked eye, they can be measured with instruments.

The wavelength of solar radiation is mainly 0.15-4 microns, of which the maximum radiation wavelength is 0.5 microns on average; the wavelength of ground and atmospheric radiation is mainly 3-120 microns, of which the maximum radiation wavelength is 10 microns on average. It is customary to call the former shortwave radiation and the latter longwave radiation.

Third addition: Oh, the information is more complete.

A: What is the difference between electromagnetic radiation and electromagnetic radiation pollution?

Q: In fact, electromagnetic radiation and electromagnetic radiation pollution are two concepts. Any electrified object has electromagnetic radiation. When the intensity of electromagnetic radiation exceeds the national standard, it will produce negative effects and cause different diseases and harm to the human body. , this part of the radiation that exceeds the standard electromagnetic field intensity is called electromagnetic radiation pollution.

A: What impact does mobile phone base station radiation have on the human body?

Q: This is a relatively common phenomenon. Many residential buildings in urban areas have mobile phone base stations installed on them. Some citizens are worried about whether the electromagnetic radiation generated by such devices will harm the human body. In fact, there is no need to worry about this issue. The difference between cell phone radiation and cell phone base station radiation. Generally, the electromagnetic radiation value of a mobile phone is between 0.03-0.7, while the radiation value of a mobile phone base station is 10 microwatts. The radiation value produced by a mobile phone base station is not much higher than that of a mobile phone! In addition, the closer the electromagnetic radiation is, the longer the exposure time is, and the deeper the damage will be! The mobile phone base stations installed on the roofs of ordinary residential buildings are a safe distance from us, so everyone can rest assured!

Electrical appliance radiation index

The electrical appliance radiation index is based on a five-point scale. Anything rated five points is a serious exceedance, which needs your attention; three or more stars are also considered excessive. The range should also attract your attention; one-star ones are safe and you can use them with confidence.

Electromagnetic radiation is divided into two levels. The unit of the industrial frequency band is μT. If the radiation is above 0.4μT, it is a strong radiation, which is harmful to the human body. Long-term exposure is prone to leukemia. If the radiation is below 0.4μT, it is relatively safe. The unit of radio frequency electromagnetic waves is μW/㎝2.

1. Television

Traditional picture tube TV CRT was the first to be tested. We first tested it at close range. Within half a meter from the front, the radiation value it produces is 0.12μT when it is turned on normally, the radiation value during normal viewing is 0.30μT, and the radiation value when changing channels is 0.27μT. The standby state is 0.11μT, while under normal viewing conditions, the radiation value is 0.28μT, which overall seems to be close to the warning value.

Because most people watch TV at a distance of about 3 meters, we also conducted tests at a distance of 3 meters from the front and found that the radiation is attenuated to a great extent: turning on and off, watching normally, and changing channels , standby state are all 0.12μT. The test results show that normal viewing of traditional picture tube TVs will not cause harm. But what surprised us was that the radiation intensity was higher behind it. The radiation value reached 4.8μT within half a meter after it was turned on. Moreover, the radiation did not decrease across glass or wooden boards, even across a 10 cm thick wall. The radiation value is still 0.9μT. Be careful if the back of your TV is facing the bedside in your bedroom. But usually people have different times of resting and watching TV, so it's not a big problem.

Looking at the plasma TV again, half a meter from the front, it is 0.11μT when turning on, watching, and changing channels, 0.12μT in standby, and 0.11μT on the side; 3 meters from the front, it is 0.12μT when turning on, and normal viewing. It is 0.14μT when changing channels and 0.11μT when in standby mode. From the test results, it can be seen that compared with traditional TVs, the radiation intensity of plasma is smaller.

As for a rear projection TV, when viewed normally, it is 0.12μT close to the front of the fuselage, 0.19μT on the sides, and 0.14μT on the back; 0.11μT at half a meter from the front; 0.1μT at 3 meters from the front.

The most reassuring among the TV series is the LCD TV. Whether it is within half a meter from the front or 3 meters from the front, the test results at the moment of power-on, normal viewing, channel changing, and standby state are all 0.1 μT, and the side is only 0.11μT, basically the radiation intensity does not change.

Test results: After comparing the three TVs, it is not difficult to find that LCD TVs and rear-projection TVs have the smallest radiation, plasma TVs have slightly stronger radiation, and CRT TVs are larger, but mainly behind the TV. Tips It's best to keep a distance when watching, especially children.

2. Video player and home theater

In recent years, home theater has become popular, that is, a video player plus a sound system. According to the test results, DVD1.2μT, OK player 1.2μT , the power amplifier is 1.24μT, the small speaker is 1.5μT, and the large speaker is 0.49μT. If they are turned on at the same time, the radiation will be quite large.

Tip: It is recommended that you use the home theater as little as possible. If you want to sing, it is best to go to a KTV.

CRT monitor, LCD monitor, desktop computer host, small speaker, laptop computer

People have always believed that CRT monitors have greater radiation. Is this true? We first tested it, with 1.00μT pressed against the front of the display and 0.55μT pressed against the side of the display, which is not small! Looking at the center of the display screen, at a distance of 0.03 meters, the radiation is still 0.55μT. Is this CRT monitor really as radiant as we imagined? In order to further confirm, we started to look for its safe distance, and found that at a distance of 0.2 meters, the radiation in front of the display screen attenuated to 0.18μT. It seems that the CRT monitor can be used with confidence as long as the distance of 0.2 meters is maintained. Some viewers asked whether the radiation from the rear is larger like a CRT TV. After testing, it was found that it was not. Some people like to use radiation-proof screensavers, but does it work? We also specially tested it. In addition, the screen saver radiation is only reduced by 10%. It seems that the screen saver is not very effective.

The radiation index of CRT monitors: ★★★☆☆

Nowadays, LCD monitors are replacing traditional monitors, and we have also tested them. 0.11μT at 0.5 meters in front of the display, 0.12μT at startup, 0.11μT at shutdown, and 0.12μT at 0.5 meters from the side of the display. It seems that the LCD is really reassuring.

The radiation index of the LCD monitor: ★☆☆☆☆

Let us look at the desktop computer host again, the front is 0.17μT, but the radiation in the center of the host operating panel is slightly stronger, with a distance of 0.03 meter, 0.26μT; the side of the host is 0.29μT, the center of the left side of the chassis, the distance is 0.03 meters, 0.23μT. The back is 0.46μT, but we are generally a certain distance from the back of the host, so the impact is not big. There are also 0.17μT at the moment of power-on and in standby state. Another thing to mention is that if the power supply connection of a desktop computer is turned on again, the radiation is 0.47μT, so keep a distance when using the desktop computer.

The radiation index of the desktop computer host: ★★★☆☆

However, the next test is not very optimistic. The subwoofer speaker, the center of the operation panel, the distance 0.03 meters, 0.63μT; the center of the right side of the speaker, distance is 0.03 meters, 5.68μT; the radiation is not small, so what is its safe distance? After careful testing, it was found that when the distance is 0.4 meters, its radiation is reduced to 0.17μT. Therefore, the subwoofer speaker radiates seriously, so you must keep a distance of at least half a meter when using it.

The radiation index of the subwoofer speaker: ★★★★☆

The last thing to talk about is the laptop, 0.1 meters in front of the display screen 0.13μT, 0.3 meters in front of the display screen 0.10μT , 0.13μT at 0.3 meters on the side of the display, 0.19μT above the keyboard, and 0.22μT on the power adapter. The test results show that the radiation from the laptop keyboard is slightly stronger, and the power adapter has the largest radiation.

The radiation index of the notebook: ★☆☆☆☆

Tip: The radiation of the LCD screen is very small, and the CRT monitor is slightly larger, but they are all within the safe range; behind and on the side of the host The radiation is relatively large, so it is strongly recommended that you do not use it with the case open for the sake of heat dissipation; the subwoofer speaker radiates seriously, so keep at least half a meter away from it when using it; the radiation of a notebook is concentrated above the keyboard, so you should keep a farther distance from the power adapter when using the notebook.

Hey, by the way, computers and notebooks don’t radiate much, but that optical mouse turns red and blue for a while, which is quite scary. Is there any radiation? Do wireless mice and wireless keyboards emit less radiation than ordinary ones? And that wireless LAN transmitter! There are also digital equipment, such as digital cameras, MP3 and MP4.

Let me tell you, this kind of battery-powered DC electrical appliance is the safest.

Ordinary mouse: 0.1μT

Ordinary keyboard: 0.11μT

Wireless mouse: 0.53μT (above the mouse)

Wireless keyboard: 0.96μT (above the keyboard)

Wireless gateway: 0.15μT (above the gateway)

Also printer: 0.11μT

Digital camera power adapter: 0.11μT < /p>

MP4 power adapter: 0.16μT

Radiation index of ordinary mouse, ordinary keyboard, wireless gateway, printer, digital camera and MP4 power adapter: ★☆☆☆☆;

Radiation index of wireless mouse and wireless keyboard: ★★★☆☆

Tip: Ordinary keyboards, mice, wireless gateways, printers, digital cameras and MP4 power supplies do not radiate much, so you can rest assured use. However, wireless keyboards and wireless mice radiate relatively large amounts of radiation.

3. Refrigeration and heating appliances and electric blankets

The air conditioner is the longest-used and most powerful one in the bedroom. What is gratifying is that at the moment of turning on and off, during normal use, the air conditioner , its radiation is only 0.1μT, and the radiation value does not change much in various modes such as silent and sleep.

In winter, some families like to use small electric heaters, air heaters and other heating appliances, but their radiation is not small. Let’s take a look at the infrared electric heater first. The result of the test at a distance of 1mm is: the above The radiation is 1. 8μT, and the side is 5.4μT. The radiation intensity is very high. We also tested it 1m away, and the radiation was reduced to 0.14μT. The test result of the heater being close to it is 9. 3μT, at half a meter, 0.34μT on the front and 0.25μT on the back. But the most reassuring thing is the Youting electric heater. When used in high-end, the upper center is 0.19μT; the side center is 0.18μT when close to it, and 0.18μT when half a meter away.

When the electric blanket is used at high level, the temperature near the power supply is 0.71μT, the left corner opposite to the power supply is 1.15μT, the right corner opposite to the power supply is 0.71μT, and the central part of the electric blanket is 0.55μT; The left corner of the power supply is 0.70μT, and the right corner of the opposite side of the power supply is 0.49μT. It seems that the radiation from the electric blanket is really quite large.

Another large radiation source in the bedroom is the electric fan, which is 2.6μT at low wind speed and 0.9μT at high wind speed; however, the radiation attenuates to 0.11μT at a distance of 2m.

Tip: The radiation of air conditioners is small and can be used with confidence. However, the radiation of infrared tube electric heaters, heaters and fans is relatively large. It is recommended to keep a distance of at least one meter when using them. Electric blankets also emit large amounts of radiation, so it is recommended to use them sparingly.

Humidifier, air purifier

In the test, we found that this fan humidifier has the largest radiation. The result of the test close to it is 49μT, 15μT when using low-end, and 15μT when using high-end. It is 32μT when used, but it is reduced to 0.52μT at a distance of 1m. The ultrasonic spray humidifier tested close to it and the result was 9μT, and 1 meter away was 0.22μT. The air purifier was tested close to it and the result was 0.35μT, and within a range of 0.5m it was reduced to 0.12μT.

Tip: Humidifiers and air purifiers should not be placed too close to the human body.

Humidifier radiation index: ★★★★★

Air purifier radiation index: ★★★☆☆

Induction cooker, electric hot pot, microwave oven

People who like to use induction cookers to eat hot pot should pay attention. Its radiation is not small. Take a look at the test results. 0.1 meters above the induction cooker is 2.80μT, 0.3 meters above the induction cooker is 1.40μT, and the direct front of the induction cooker is 8.70μT. 0.3 meters directly in front of the induction cooker 1.00μT. Looking at the test of the electric hot pot, the high level is 0.53μT when it is turned on and 0.13μT when it is turned off.

The test results show that induction cookers have greater radiation, and electric hot pots are better than induction cookers.

Then we first tested the microwave oven that everyone is most concerned about, and found that the radiation is the largest at the door crack of the microwave oven, so we conducted a detailed test:

At mid-range firepower: 0.03 meters in front of the door crack. 17.32μW/㎝2,

0.3 meters in front of the door crack: 2.01μW/㎝2

1 meter in front of the door crack: 0.41μW/㎝2

Microwave oven Center of the door: 1 meter away from the door 150.7μW/㎝2

The test results show that the microwave oven radiates the most when it is started (the value (0.05m away from the door) is about 18 to 22μW/㎝2,).

Tip: Induction cookers have relatively large radiation, and electric hot pots are relatively small. It is recommended not to use induction cookers and electric hot pots for too long, and to keep a certain distance when using them. The microwave radiates the most when it is turned on. It is recommended that you do not get too close when cooking in the microwave.

Radiation index: ★★★★★★★

Refrigerator, range hood, ozone disinfection cabinet, ozone machine, rice cooker, electric cake pan, electric kettle, juicer, soy milk machine

< p>Refrigerator: 0.13μT outside the door and 0.16μT inside the door (opening the door)

Cooker hood: 0.38μT 0.1m in front when turned on, 0.11μT 0.1m in front when turned off

Ozone disinfection cabinet: open the door 0.14μT

Ozone machine: (open the lid) 0.55μT

Rice cooker: (front) 0.16μT

Electric baking pan: (top Closely attached) 3.60μT

Electric kettle: (closely attached) 1.20μT; (0.1 meter) 0.30μT

Juicer: 10.00μT

Soybean milk machine: (closely attached) 0.86μT; (0.1 meter) 0.30μT

Tips: Refrigerators, ozone disinfection cabinets, and rice cookers have low radiation and can be used with confidence; electric baking pans and range hoods have slightly smaller radiation If it is larger, it falls within the warning range. Be careful not to stick it too close when using it; ozone machines, soy milk machines, and juicers all have high radiation, so it is best not to let children use them.

Vacuum cleaners, electric irons, hair dryers, power strips

We previously tested this large vacuum cleaner, and the radiation under normal use was 15μT, which is not small; it is still How much radiation does this popular small handheld vacuum cleaner have? We have also done tests. The distance at the handle is 0.03 meters: 6.64μT; the center of the left side: 4.22μT; but if you use it like this, its radiation can attenuate to a safe range, and the distance at the back 0.2 meters: 0.15μT.

The radiation index of a large vacuum cleaner: ★★★★★

The radiation index of a small vacuum cleaner: ★★★★☆

The radiation of an electric iron is also quite large , we did another detailed test and found that the radiation of the electric iron will increase when it is heated. When it is heated, the handle is 1.22μT; but when it is at constant temperature, the radiation attenuates to 0.12μT. Therefore, if you are ironing clothes, it is best to heat the temperature to the right level at one time and then continue to heat it for a while. Never iron clothes while heating.

The radiation index of the electric iron: ★★★★☆

The hair dryer is also a large radiation source we found. In the previous test, the low-end was 4.20μT and the high-end was 10.00μT; later it was When using the hot air setting, a detailed test was conducted on different parts of the hair dryer. The handle at 0.03 meters was 10.95 μT; the air outlet was 7.16 μT. It seems that the hair dryer should be used less.

The radiation index of the hair dryer: ★★★★★

One more thing to remind everyone is that the power connection board, if no electrical equipment is connected, should be kept at a distance of 0.03 meters. Its radiation is only 0.11μT, which is not large; but when high-power electrical equipment is connected, its radiation can be 1.25μT at a distance of 0.03 meters. This is something that needs your attention.

The radiation index of the power connection board (when in use): ★★★★☆

Text: The radiation of vacuum cleaners and hair dryers is relatively large, and the radiation of electric irons is also not small. Keep away from children when using it. The radiation from the power wiring board should also draw your attention. Do not place it at the head of the bed.

Electric heated foot basin, treadmill, fat exercise machine

This is the popular electric heated foot basin. Let us see how much radiation it emits? 0.03 meters from power line, 2.20μT.

Radiation index of electric heated foot basin: ★★★☆☆

Some people like to exercise at home. How much radiation does this treadmill have? When the treadmill is working, the panel is 0.15μT, the front of the conveyor belt is 3.90μT, and the tail of the conveyor belt is 0.11μT.

The radiation index of the treadmill: ★★☆☆☆

Ladies love beauty and always like to lose weight. Let us see how much radiation the fat exercise machine has? Fat exercise machine, side, high speed, 0.03 meters, 5.48μT.

The radiation index of the fat exercise machine: ★★★★★

Tip: The radiation of the electric foot basin and the fat exercise machine are relatively large, and the front part of the treadmill conveyor belt has greater radiation.

Does a spectrum analyzer or something like that emit very little radiation?

In fact, as long as it is infrared, it is not within our test range, and what it produces is not electromagnetic radiation. So, you can use it without any worries.

4. Lamps

Let’s start with the desk lamp. This is the desk lamp for the master bedroom. Its radiation value is 0.17μT. This is an energy-saving eye protection desk lamp for children. Its The radiation value is also 0.11μT. The old-fashioned desk lamp used in the study room has a radiation of 0.1μT.

The test results of fluorescent lamps are: 0.12μT in the master bedroom, 0.18μT in the living room, and 0.11μT in the study. There are also cartoon wall lamps that children like, and their radiation value is 0.11μT.

Tip: The radiation of all lamps is qualified and can be used with confidence.

It doesn’t cost anything to avoid. One of the most effective ways is to keep a distance, and it must be a safe distance of more than 3 meters.

Then you need to make reasonable arrangements at home, because experts suggest that it is best not to wear protective clothing. The human body itself is a large conductor. Wearing it can only introduce shielded radiation into the body, and there is no such thing now. The material standards of protective clothing are clear, and the prices vary, so it is recommended that you do not trust the role of protective clothing.

Sweat! ! !

All objects in nature, as long as their temperature is above absolute zero, are constantly transmitting heat in the form of electromagnetic waves. This method of transmitting energy is called radiation. The energy emitted by objects through radiation is called radiant energy.