问题
名词解释
电磁波
答案
参考答案：
是英国物理学家麦克斯韦提出的概念。他说，如果空间某处存在一个变化的电场，它将在周围激发出一个变化的磁场，这变化的磁场又在周围激发出一个变化的电场，这样就会连续出现电场和磁场的振动，以原先的变化电场为中心向四面八方传播，这就是电磁波。电磁波传播的速度等于光速。
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电磁波
参考答案：
是英国物理学家麦克斯韦提出的概念。他说，如果空间某处存在一个变化的电场，它将在周围激发出一个变化的磁场，这变化的磁场又在周围激发出一个变化的电场，这样就会连续出现电场和磁场的振动，以原先的变化电场为中心向四面八方传播，这就是电磁波。电磁波传播的速度等于光速。
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| Chairman Mao once said, "It is not hard to do one good deed. It is hard to do good deeds all your life." Guo Mingyi, a 52-year-old worker in Anshan, Liaoning did just that. Over the past 20 years, Guo 1 60,000 mL of blood (血). That is the blood of 10 people put together. Once, 2 the cold winter of 2009,Guo got a call from the hospital. The doctors told him 3 a patient needed a blood donation. Guo didn't have time to have lunch. He traveled in the snow to 4 the hospital. When he finished donating the blood, he was 5 tired that he fell asleep on the hospital bed. Guo and his family live a 6 life. They live in a house of only 40 square meters. 7 they don't have a lot of money, Guo saves money to support poor children. In the past 16 years, he has given away over 100,000yuan to more than 180 poor students. When the parents met him, many cried, "He looks 8 than us."they said. Guo has also offered help to thousands of workers, friends and strangers. His warm heart has moved many people. They 9 him a "Modern-Day Lei Feng". Recently, Chinese leaders called on people to learn from Guo. They say young people especially should learn his selfless devotion (奉献). But Guo said he did these things in order not to get famous. "It's just that some people need some help, and there should be someone standing out to give 10 a hand." he said. | ||||
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