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第一章单元测验

1、单选题：
‏电视节目应该是什么？‍
选项：
A: 电视上策划的节目
B: 电视台录制的节目
C: 电视台或者影视制作公司录制的可供人们感知和理解的视听作品
D: 传播人们向上的节目
答案: 【 电视台或者影视制作公司录制的可供人们感知和理解的视听作品】点我阅读全文

Scanning

1、单选题：
‏Read the passage "The Discovery of X-rays" quickly and choose the paragraph(s) which contain(s) the answer(s). You may choose more than one answer for question 3. ‍‏‍The Discovery of X-rays‍‏ ‍Par. 1 Except for a brief description of the Compton effect, and a few other remarks, we have postponed the discussion of X-rays until the present chapter because it is particularly convenient to treat X-ray spectra after treating optical spectra. Although this ordering may have given the reader a distorted impression of the historical importance of X-rays, this impression will be corrected shortly as we describe the crucial role played by X-rays in the development of modern physics.‍Par. 2 X-rays were discovered in 1895 by Roentgen while studying the phenomena of gaseous discharge. Using a cathode ray tube with a high voltage of several tens of kilovolts, he noticed that salts of barium would fluoresce when brought near the tube, although nothing visible was emitted by the tube. This effect persisted when the tube was wrapped with a layer of black cardboard. Roentgen soon established that the agency responsible for the fluorescence originated at the point at which the stream of energetic electrons struck the glass wall of the tube. Because of its unknown nature, he gave this agency the name X-rays. He found that X-rays could manifest themselves by darkening wrapped photographic plates, discharging charged electroscopes, as well as by causing fluorescence in a number of different substances. He also found that X-rays can penetrate considerable thicknesses of materials of low atomic number, whereas substances of high atomic number are relatively opaque. Roentgen took the first steps in identifying the nature of X-rays by using a system of slits to show that (1) they travel in straight lines, and that (2) they are uncharged, because they are not deflected by electric or magnetic fields.‍Par. 3 The discovery of X-rays aroused the interest of all physicists, and many joined in the investigation of their properties. In 1899 Haga and Wind performed a single slit diffraction experiment with X-rays which showed that (3) X-rays are a wave motion phenomenon, and, from the size of the diffraction pattern, their wavelength could be estimated to be 10-8 cm. In 1906 Barkla proved that (4) the waves are transverse by showing that they can be polarized by scattering from many materials.‍Par. 4 There is, of course, no longer anything unknown about the nature of X-rays. They are electromagnetic radiation of exactly the same nature as visible light, except that their wavelength is several orders of magnitude shorter. This conclusion follows from comparing properties 1 through 4 with the similar properties of visible light, but it was actually postulated by Thomson several years before all these properties were known. Thomson argued that X-rays are electromagnetic radiation because such radiation would be expected to be emitted from the point at which the electrons strike the wall of a cathode ray tube. At this point, the electrons suffer very violent accelerations in coming to a stop and, according to classical electromagnetic theory, all accelerated charged particles emit electromagnetic radiations. We shall see later that this explanation of the production of X-rays is at least partially correct.‍Par. 5 In common with other electromagnetic radiations, X-rays exhibit particle-like aspects as well as wave-like aspects. The reader will recall that the Compton effect, which is one of the most convincing demonstrations of the existence of quanta, was originally observed with electromagnetic radiation in the X-ray region of wavelengths.‍‏‍‏When were X-rays discovered?‍
选项：
A: Par. 1
B: Par. 2
C: Par. 3
D: Par. 4
E: Par. 5
答案: 【 Par. 2】点我阅读全文

1.1手持示波器的使用

1、单选题：
3.     为使扫描线性良好，在一个周期内扫描输出电压随时间变化而增加的速度是一个（     ）的量。‌‎‌
选项：
A: 均匀变化
B: 线性变化
C: 线性上升
D: 恒定不变
答案: 【 恒定不变】点我阅读全文

1~2单元测验

1、单选题：
‎第一届全国大学生机械创新大赛于（   ）举行。‌
选项：
A: 2000年
B: 2002年
C: 2004年
D: 2006年
答案: 【 2004年】点我阅读全文

引言单元测试

1、单选题：
液压传动是利用液体的        来传递能量；液力传动是利用液体的        来传递能量。​‏​
选项：
A: 动能；热能
B: 动能；压力能
C: 压力能；势能
D: 压力能；动能
答案: 【 压力能；动能】点我阅读全文

第一讲测验题

1、单选题：
有三个直径相同的金属小球。小球1和2带等量同号电荷，两者的距离远大于小球直径，相互作用力为F。小球3不带电，装有绝缘手柄。用小球3先和小球1碰一下，接着又和小球2碰一下，然后移去。则此时小球1和2之间的相互作用力为：
选项：
A: 3F/8
B: F/4
C: F/2
D: 3F/4
答案: 【 3F/8】点我阅读全文

单元测验1

1、判断题：
‍In general, there are two ways to learn about target culture: intelligent approach and experiential approach.​
选项：
A: 正确
B: 错误
答案: 【 错误】点我阅读全文

小测验1.1

1、单选题：
‏对于：​int a[] = {5, 15, 34, 54, 14, 2, 52, 72};
int *p = &a[5];‏则：​‏p[-2]的值是？​‏​
选项：
A: 编译出错，因为数组下标越界了
B: 运行出错，因为数组下标越界了
C: 54
D: 2
答案: 【 54】点我阅读全文

第一章 反对外国侵略的斗争 随堂测验

1、单选题：
‌英国发动鸦片战争的主要目的是：‌
选项：
A: 保护鸦片贸易
B: 打开中国商品市场
C: 割占中国领土
D: 争取外交礼仪平等
答案: 【 打开中国商品市场】点我阅读全文

单元测试 力学基本定律

1、单选题：

​

‍选项：
A:
B:
C:
D:
答案: 【 】点我阅读全文