试题与答案

如右图所示,带有正电荷的A粒子和B粒子同时以同样大小的速度从宽度为d的有界匀强磁

题型:选择题

题目:

如右图所示,带有正电荷的A粒子和B粒子同时以同样大小的速度从宽度为d的有界匀强磁场的边界上的O点分别以30°和60°(与边界的交角)射入磁场,又恰好不从另一边界飞出,则下列说法中正确的是          (    )

A.A、B两粒子在磁场中做圆周运动的半径之比是

B.A、B两粒子在磁场中做圆周运动的半径之比是

C.A、B两粒子的之比是

D.A、B两粒子的之比是

答案:

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参考答案:D解析:本题考查要点是"威灵仙的主治病证"。(1)桑枝的主治病证:①风湿痹痛;②水肿,脚气浮肿。(2)络石藤的主治病证:①风湿痹痛,筋脉拘挛;②喉痹,痈肿。(3)独活的主治病证:①风寒湿痹,腰...

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      Mary is a student. She lives far from her school. So she often goes to school by bus. She gets up at 6: 30

every morning. She doesn't want to be late.

      The first class starts at eight and there are four classes in the morning and three in the afternoon. She

doesn't go home for lunch. She has lunch at school.

      Mary studies Chinese, English, math and other lessons at school. She studies hard.

      In the evening, she usually does her homework. Sometimes she watches TV. She goes to bed early.

1. How does Mary go to school?

A. By ship.

B. By bus.

C. By bike.

2. Mary _____________ at 6: 30 every morning.

A. gets up

B. goes to school

C. goes home

3. Mary has lunch _____________.

A. at home

B. at school

C. in the park

4. Mary usually does her homework _____________.

A. in the morning

B. in the afternoon

C. in the evening

5. Does Mary go to bed early? 

A. No, she doesn't.

B. Yes, he does.

C. Yes, she does.

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