Carbon intensity is defined as the amount of greenhouse gases emitted for each unit of nation income.

VOA: standard.2009.11.26

So that means we're going to need to figure out what is the energy per photon that's emitted by that UV light.

所以那意味着我们将需要,计算出从紫外光源发射出的,每个光子的能量。

麻省理工公开课 - 化学原理课程节选

So our last question we ask is what's the total number of photons emitted if we give this given intensity for 60 seconds?

最好的问题是如果我们,按照给定的强度照射60秒,那么总的光子数是多少？

麻省理工公开课 - 化学原理课程节选

Complimented, my eye. She kissed me on my pure brow," and my darling emitted that new yelp of merriment which, perhaps in connection with her theatrical mannerisms, she had lately begun to affect."

是的，夸奖我的眼睛，她亲吻了我漂亮的眉毛“,我亲爱的洛丽塔发出了欢快的叫喊声，那也许和她戏剧性的行为方式有关，她随后开始变得做作起来“

耶鲁公开课 - 1945年后的美国小说课程节选

What about the energy of the emitted photons?

发射光子的能量怎么样？

麻省理工公开课 - 固态化学导论课程节选

So this means that we can go directly from the energy between two levels to the frequency of the photon that's emitted when you go between those levels.

这意味着我们可以直接,从两个能级的能量得到它们之间,跃迁发射出光子的频率。

麻省理工公开课 - 化学原理课程节选

And what we predict as an energy difference between two levels, we know should correspond to the energy of light that's either emitted, if we're giving off a photon, or that's absorbed if we're going to take on a photon and jump from a lower to a higher energy level.

我们预测，两个能级之间的能量差，我们知道，它要么和发出的光有关,如果它发出光子的话，要么它吸收光子,从低能级跃迁到，更高能级上去。

麻省理工公开课 - 化学原理课程节选

So we can figure out the energy of each photon emitted by our UV lamp by saying e is equal to h c over wavelength.

所以我们可以计算出,每个从紫外光源射出的光子,也就是e等于h乘以c除以波长。

麻省理工公开课 - 化学原理课程节选

Also, what's the energy per photon of this red laser pointer, and then it's also worth trying a calculation dealing with intensity. So let's also try calculating the numbers of photons that would be emitted by this laser pointer, if, for example, we were to use it for 60 seconds and this were a one milliwatt laser.

同样，红色激光笔的,每个光子能量是多少，这也值得用处理强度的方法计算一下,让我们也计算一下,有多少光子会从这个激光笔射出，举个例子，如果我们使用它持续60秒,这里会有一毫瓦的激光。

麻省理工公开课 - 化学原理课程节选

So what we'll do is this problem here, which is let's calculate out what the wavelength of radiation n would be emitted from a hydrogen atom if we start at the n equals 3 level and we go down to the n equals 2 level.

我们来做这个问题,让我们来计算一下,从n等于3到,等于2能级氢原子辐射的波长是多少。

麻省理工公开课 - 化学原理课程节选

You don't need to know those, but just because it's a special case with the hydrogen atom, they do tend to be named -- the most important, of course, tends to be the Balmer series because that's what we can actually see being emitted from the hydrogen atom.

你们不需要记住,但因为这是氢原子的特例,人们想要命名它，最重要的是当然是Balmer系,因为它是我们可以看到的,从氢原子放出来的光谱。

麻省理工公开课 - 化学原理课程节选