mooc标签存档订阅

单元测验

1、单选题：
（）是为了有效地完成各种技术动作而采取的起始身体姿势。‏
选项：
A: 移动
B: 滑步
C: 快速起动姿势
D: 准备姿势
答案: 【 准备姿势】点我阅读全文

第一章单元测验

1、单选题：
​稀缺性问题是______问题。‌
选项：
A: 由于价格过低而产生的
B: 只有贫穷的国家才会发生的
C: 可以通过市场交换而被消除的
D: 所有国家和个人在过去、现在和可见的未来都将面对的
答案: 【 所有国家和个人在过去、现在和可见的未来都将面对的】点我阅读全文

课后测一测

1、单选题：
‎下列哪行代码不能出现右侧的效果？‌
选项：
A:  print("@")print("@")
B:  print('@n@')
C: print("@  @")
D: print("@@")
答案: 【 print("@  @")】点我阅读全文

MOOC第一章单元测试题

1、单选题：
执行下面的程序段的时间复杂度为（   ）。‏for(int i=0;i<m;i++)‏   for(int j=0;j<n;j++)‏     a[i][j]=i*j;‏‌‏
选项：
A: O(m2)
B: O(n2)
C: O(m*n)
D: O(m+n)
答案: 【 O(m*n)】点我阅读全文

第二章单元测验

1、单选题：
‏从事生产、经营的纳税人领取工商营业执照（含临时工商营业执照）的，应当自领取工商营业执照之日起（     ）内申报办理税务登记。​
选项：
A: 15日
B: 30日
C: 60日
D: 180日
答案: 【 30日】点我阅读全文

基本不等式

1、填空题：

‍已知a>0,b>0，且满足a+b=1，的最小值为         

‎答案: 【 9】点我阅读全文

第一章单元测验

1、单选题：
‍会计的基本职能是（    ）。‌
选项：
A: 决策与控制   
B: 分析与考核
C: 核算与监督  
D: 预算与计划
答案: 【 核算与监督  】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

绪论单元测试

1、单选题：
提出“灭人之国，必先去其史”警言的著名学者是：‍
选项：
A: 顾炎武
B: 龚自珍
C: 梁启超
D: 陈寅恪
答案: 【 龚自珍】点我阅读全文

第一章扬琴的古诗

1、判断题：
‍视频中的诗句“发声亦自循宫商”，其中宫商指代朝代？‌
选项：
A: 正确
B: 错误
答案: 【 错误】点我阅读全文