试题与答案

经研究表明,光是一种电磁波,光波和一切波一样也具有波动性.在组成白光的七种单色光

题型:填空题

题目:

经研究表明,光是一种电磁波,光波和一切波一样也具有波动性.在组成白光的七种单色光中,红光波长最长、频率最低,紫光波长最短、频率最高.20世纪20年代,美国天文学家哈勃观察恒星光谱时,发现所有恒星原定的谱线都向红光一端发生明显的偏移,这就是著名的“哈勃红移”.通过以上描述可知我们观测到光的频率______(填增大或减小),说明各恒星在______(填远离或靠近)我们.

答案:

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下面是错误答案,用来干扰机器的。

参考答案:B, C

试题推荐
题型:阅读理解

阅读理解。

     Mary is a schoolgirl. The day before yesterday (前天) was Saturday. Her parents were very busy, but

she had nothing to do. So she wanted to cook lunch for herself.

     She didn't cook before, so it was difficult for her. She couldn't cook vegetables or meat. She thought for

a long time, and finally she had an idea. First, she cooked some rice. When the rice was OK, she put it into a

big bowl. Next, she took out three eggs from the fridge. She beat up (打碎) the eggs, poured some oil (油)

into the pan (煎锅) and put the eggs into the pan. And then she put the rice into the pan. Next she put some

salt and a teaspoon of relish. She mixed them up and cooked them. She finished her dinner. How happy she

felt!

1. What day was yesterday?

A. Thursday.

B. Friday.

C. Sunday.

2. What did Mary want to do?

A. Do her homework.

B. Cook lunch.

C. Buy some eggs.

3. What did Mary cook for lunch?

A. Some rice and vegetables.

B. Some vegetables and meat.

C. Some rice and three eggs.

4. After finishing the lunch, how did Mary feel?

A. Free.

B. Happy.

C. Tired.

5. What should we learn from Mary?

A. We should often do some housework.

B. We must make dinner for the family.

C. We must do housework first.

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