问题
选择题
电场强度的定义式为
，则[ ]
A、该定义式只适用于点电荷产生的电场
B、F是试探电荷所受到的力，q是产生电场的电荷电量
C、场强的方向与F的方向相同，场强的大小E与F成正比，与q成反比
D、由该定义式可知，场中某点电荷所受的电场力大小与该点场强的大小成正比
答案
答案：D
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电场强度的定义式为，则[ ]
A、该定义式只适用于点电荷产生的电场
B、F是试探电荷所受到的力，q是产生电场的电荷电量
C、场强的方向与F的方向相同，场强的大小E与F成正比，与q成反比
D、由该定义式可知，场中某点电荷所受的电场力大小与该点场强的大小成正比
答案：D
There are many kinds of friends. Some are always 36 you, but don't understand you. Some say only a few words to you, but understand you. Many people will step in your life, but only 37 friends leave footprints. I shall always recall (回忆) the autumn and the girl with the 38 . She will always bring back the friendship between us. I know she will always be my best friend. It was the golden season. I could see the yellow leaves 39 on the cool 40 . In such a season, I liked walking alone in the leaves, 41 to the sound of them. Autumn is a 42 season and life is uninteresting. The free days always get me 43 . But one day, the sound of a violin 44 into my ears like a stream (小溪) flowing in the mountains. I was so surprised that I jumped to see what it was. A young girl, standing in the wind, was 45 in playing her violin. I had 46 seen her before. The music was so nice that I listened quietly. Lost in the music, I didn't know that I had been 47 there for so long but my existence (存在) did not seem to disturb her. Leaves were still falling. Every day she played the violin in the corner of the building 48 I went downstairs to watch her performance. I was the only listener. The autumn seemed no longer lonely and life became 49 . 50 we didn't know each other, I thought we were already good friends. I believe she also loved me. Autumn was nearly over. One day, when I was listening carefully, the sound suddenly 51 . To my astonishment (惊讶), the girl came over to me. “You must like violin.” she said. “Yes. And you play very well. Why did you stop?” I asked. Suddenly, a 52 expression appeared on her face and I could feel something unusual. “I came here to see my grandmother, but now I must leave. I once played very badly. It was your listening every day that 53 me.” she said. “In fact, it was your playing 54 gave me a meaningful autumn,” I answered, “Let's be friends.” The girl smiled, and so did I. I never heard her play again in my life. I no longer went downstairs to listen like before. Only thick leaves were left behind. But I will always remember the fine figure (身影) of the girl. She is like a 55 —so short, so bright, like a shooting star giving off so much light that it makes the autumn beautiful.
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