题干

下列关于光现象的说法中,正确的是(  

A:“坐井观天,所见甚小”是光直线传播的结果

B:验钞机是利用红外线使钞票上的荧光物质发光从而辨别钞票的真伪的

C:光与镜面成30°角射到平面镜上时,其反射角为30°

D:筷子斜插入装满水的碗中,我们可以观察到筷子在水中的部分会向下偏折

上一题 下一题 0.0难度 选择题 更新时间:2019-12-05 12:49:42

答案(点此获取答案解析)

A

同类题4

    Your junior high school years are coming to an end. After the big exam, most of you will go on to study in a senior school. What are you   expecting from senior high school? Let's hear some teen readers talk about it.
Zhou Zhijie, 15, from Shanghai:
    I have heard that although Senior 3 is a hard year, Senior 1 and Senior 2 are less stressful. I hope there'll be time then to enjoy sports. There will be plenty to see. Especially, the World Cup in Brazil is coming. We can watch football matches. I'm sure I'll really enjoy it.
Jin Xi, 16, from Harbin, Heilongjiang:
    I really enjoy science. I visit many science exhibitions. I am interested in UFOs, too. I'm crazy about making model planes, although I'm not very good at it because I don't really have enough scientific knowledge. I'll be learning more science in senior high school. In a word, sometime in the future I'm going to build an excellent model plane!
Wang Yaling, 15, from Xiamen, Fujian:
    I hope I can be taller in senior high school. I'm only 155cm. Many people grow faster in senior and I hope I will, too. I want to be 162cm. But I'm not sure about that, since most girls in my family don't grow taller than 160cm. I hope I'm different.
Zhang Fang, 15, from Hebi, Henan:
    I expect that I'll make more friends in senior high school. I study in a middle school in the country. Most of my classmates live nearby. In senior high school, I'll meet different people from different areas. I hope I can learn new things from them.
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