Сборник задач по подготовке учащихся к международным исследованиям timss и pisa
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- Task 17: Ultrasound
| Task 16: Electromagnetic waves
The impact of electromagnetic fields on human health is the investigated scientific problem. With the rapid growth of numbers of technologies and devices it is impossible to avoid the influence of the electromagnetic field in the world today. Today a number of international standards and requirements is developed in order to prevent any influence of the electromagnetic field on a humanbeing , so almost all household appliance is appropriate with the requirements. However, from the viewpoint of the emitted radiation, they are still a source of danger, so it is necessary 160 to fallow basic rules when dealing with a variety of video display terminals. 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 shown by ultrasonic scanning. Ultrasound is considered as a safe for both the mother and the fetus. The doctor holds the sensor and leads it along the mother's abdomen. 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 females during pregnancy it is highly recommended avoiding abdominal investigation by X-rays. Question: Explain why should a pregnant woman avoid abdominal x-ray examination? Answer:_____________________________________________________ жүктеу/скачать 3,47 Mb. Достарыңызбен бөлісу:
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