Сборник задач по подготовке учащихся к международным исследованиям timss и pisa
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- Task 17: Ultrasound
| Task 16: Hertzian waves
The impact of electromagnetic fields on human health - it is the investigated scientific problem. With the rapid growth of numbers of technologies and devices is a virtually impossible to avoid the influence of the electromagnetic field in the world today. Today already developed a number of international standards and requirements in order to prevent whatsoever influence of the electromagnetic field to a human, so almost all household appliance is consistent with the requirements. However, from the viewpoint of the emitted radiation, they still are a source of danger, so it is necessary comply basic rules when dealing with a variety of video display terminals. 159 Do not stand behind the working monitor, all electromagnetic radiation hit it from the back side. Everyone should take care of their health. Question: What effect has the electromagnetic field on the human? Answer:_______________________________________________ Task 17: Ultrasound Ultrasound. In many countries the fetal image (developing baby) can be prepared by ultrasonic scanning. Ultrasound is considered as a safe for both the mother and the fetus. The doctor holds the sensor and leads them on the mother's belly. The ultrasonic waves pass into the abdominal cavity. Inside the abdomen waves are reflected from the surface of the fetus. The reflected waves fall back to the sensor and transmitted to an apparatus which creates an image of the fetus. (pic.16) Fetal image can also be obtained by using X-rays. However, for women during pregnancy highly recommended avoiding abdominal investigation by X-rays. Question: Explain why a woman during pregnancy should avoid abdominal x- rays investigation? Answer:_____________________________________________________ жүктеу/скачать 3,45 Mb. Достарыңызбен бөлісу:
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