Because there is no equipment to monitor brain activity in the school, girls choose the seeds of Oenanthe javanica as the research object. They divided 12 plates filled with cress seeds into two groups. One group was placed in a room without any WiFi signal, and the other group was placed next to two running wireless routers. In 12 days, in the room covered with WiFi, most of the seeds turned brown; After 15 days, these brown seeds died one after another. While the seeds in the other room grow normally.
③ Although some people think that the seed died in a room covered by WiFi, it may be the reason for the heat dissipation of the router. However, the experimental results aggravated people's fear of WiFi radiation, and some parents and teachers demanded that wireless routers be banned on campus.
④ At the same time, the experiment was supported by Dutch researchers. Three years ago, Dutch scientists chose ash tree as the research object. They put these trees 0.5 meters away from six radiation sources. The frequency band of the radiator is 24 12 ~ 2472 Hz, and the power is 100 MW- similar to a wireless router. A substance with "lead luster" appeared on the gray leaves, which caused the upper and lower epidermis of the leaves to die and eventually fall off.
However, some researchers in the United States are skeptical about these findings. They believe that because WiFi uses low-intensity radio waves to transmit signals, its power is only 1% of that of microwaves. Spending a year in a room with WiFi coverage is only equivalent to talking on a mobile phone for 20 minutes.
However, it should be reminded that if WiFi is used improperly, it is very likely to cause harm to the human body. So as an ordinary user, what should you pay attention to when using a wireless router?
Firstly, the amount of radiation received by human body is related to power. The greater the power, the greater the harm. So there is no need to use a wireless router with excessive power at home.
Secondly, radiation hazards are also related to distance. The farther the distance, the less harm. If there are pregnant women, children, the elderly or people with low immunity at home, it is best to keep the wireless router away from their activities.
Pet-name ruby Third, it is best not to put WiFi devices in the bedroom, especially beside the bed. If you don't use WiFi, you'd better turn off the wireless router to reduce unnecessary risks.
Attending also, it's best to put the computer on a desk or stand, especially don't use a laptop with WiFi on its legs.
1. The following statement is in line with item (d) of the context.
A. The seeds of Oenanthe javanica died in a room covered by WiFi, which may be the reason for the heat dissipation of the router. Therefore, some parents and teachers require that wireless routers should not be installed on campus.
B. Dutch scientists used wireless routers to study their effects on ash trees, and found that the upper and lower epidermis of leaves near the routers died and eventually fell off.
C. Experiments on cress seeds by Danish female students and ash trees by Dutch scientists prove that WiFi signals are harmful to human health.
D. Some researchers in the United States think that WiFi signal radiation is small and they are skeptical about its possible harm to health.
2. The following statement is inconsistent with item (d) of the text.
A radiation hazards are related to the length of exposure time, and the longer the exposure time, the greater the hazards.
B the radiation hazard is related to the power of the radiation source, and the greater the power, the greater the hazard.
C radiation hazard is related to the distance of receiving radiation, and the farther the distance, the smaller the hazard.
D. radiation hazards are related to the frequency of radiation sources. The higher the frequency, the greater the harm.
3. The following analysis of the article is incorrect: (a)
A. This is an explanatory article about WiFi.
B paragraph (2) illustrates with examples and comparisons that WiFi signals may be harmful to health.
C paragraphs ⑦ ~ ⑩ When explaining the precautions in using wireless routers, the logical order from primary to secondary is adopted.
D. In the sixth paragraph, the phrase "it may also cause harm to human body" is an expressive word, which emphasizes the great possibility, indicating that it is easy to cause harm to human body if WiFi is used improperly.