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No, OK and that's correct, because each photon of light actually has more energy than is needed to eject an electron.
没有，好，对了，因为每一个光子实际上,都有更多的能量去逐出一个电子。
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And instead of having the electron giving off energy as a photon, instead now the electron is going to take in energy from light and move up to that higher level.
与电子以光子形式施放能量不同,我们现在要从光中,获得能量到一个更高的能级。
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Well, if I want to look at this, I want to have very accurate capabilities in terms of the energy that I use, the light that I use.
嗯，如果我想看看这个，我得有精确的观察能力,根据我用的能量，我接收的光。
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So, what we would expect is that there is a relationship between intensity in kinetic energy because it was understood that however intense the light was, if you had a more intense light, it was a higher energy light beam.
光强和能量之间,应该有一定的关系,因为在我们的理解中,不管光强是多少，光的强度越大,光束能量越高。
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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。
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The next thing that they wanted to look at was the actual intensity of the light and see what the relationship of intensity to kinetic energy is.
下一而他们要研究的是光的强度,看一下光强和能量之间的,关系是怎样的，我们预期。
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That makes sense because we're losing energy, we're going to a level lower level, so we can give off that extra in the form of light. And we can actually write the equation for what we would expect the energy for the light to be.
这很合理，因为我们在损失能量,我们要到一个更低的能级去,我们要以光的形式给出额外的能量,我们可以写下光能量的方程。
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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。
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So, if you use a black lamp or something and you excite something up to a higher energy level and then it relaxes back down to its lower energy state, it's going to emit a new wavelength of light, which is going to be visible to you.
如果你用一个紫外灯或别的,东西把某种分子激发到,更高的能级，然后它会掉回,到低能级，它就会释放,一个新的波长的光,这个光是可见的。
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So, now we can talk about it in different terms, Ei for example, talking about e sub i, which is the incident energy or the energy of the light that comes in, or talking about work function here, and that's just another way to say threshold energy.
现在我们可以从不同的方面,来谈论它了，举例来说，它是入射能量或者进来的光的能量,或者谈论这里的功函数，它是另一种描述临界能量的方式。
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Absorption is just the opposite of emission, so instead of starting at a high energy level and dropping down, when we absorb light we start low and we absorb energy to bring ourselves up to an n final that's higher.
吸收就是发射的逆过程,与从一个高能量到低能量不同，当吸收光时，我们从低能量开始,吸收能量到一个更高的能量。
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So that's the important take-away message from this slide. If we think about these different types of lights, microwave light, if it's absorbed by a molecule, is a sufficient amount of frequency and energy to get those molecules to rotate. That, of course, generates heat, so that's how your microwaves work.
重要的信息，如果我们看看,这些不同种类的光，微波,如果被分子吸收，它的频率和能量可以,使分子转动,这当然的，会产生热量,这就是你们微波炉的工作原理。
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So, for example, here we're showing rubidium and potassium and sodium plotted where we're plotting the frequency -- that's the frequency of that light that's coming into the metal versus the kinetic energy of the electron that's ejected from the surface of the metal.
让大家看来都是可以理解的事情,就是把不同金属的观测结果,画到一张图里面来，例如这里,我们展示的是钠，钾,铷的频率-这是照射金属的光的频率,和金属表面出射电子动能的关系。
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If I went on and told you what the different incident light was, and what the electrons were ejected with, and then you could look up the ionization energy for the particular different elements, you should be able to actually determine exactly which element it is, but just with the information given, we can only narrow it down to these choices here.
如果我继续告诉大家入射光源是什么，出射电子的动能是多少，那么你可以去查一查,以上各个元素的电离能，这样你就应该能确定,这个元素到底是哪个，但是只凭题目中的信息，我们只能把范围缩小至以上几种元素。
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So, one thing they did, because it was so easy to measure kinetic energy of electrons, is plot the frequency of the light against the kinetic energy of the electron that's coming off here. And in your notes and on these slides here, just for your reference, I'm just pointing out what's going to be predicted from classical physics.
他们做的其中一件事,因为测量电子动能是很容易的，就是画出光的频率,和出射电子动能之间的关系,在讲义的这里，仅仅是,为了做个比较，我要指出，经典物理所给出的预测,这个不作为对你们的要求。
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So that should mean that the energy that's transferred to the electron should be greater, but that's not what you saw at all, and what you saw is that if you kept the frequency constant there was absolutely no change in the kinetic energy of the electrons, no matter how high up you had the intensity of the light go.
所以这意味着转移到电子,上的能量也越大，但这并不是，我们观测到的现象,我们所看到的是,如果固定光的频率不变,不管光强如何变化,电子的动能没有任何变化。
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Well, we can't guarantee with UV light we'll have enough energy to eject every single electron, so that's why when we use x-rays, they're higher energy, you can pretty much be guaranteed we're going to eject all of those electrons there.
好，我们不能保证紫外光有足够的能量,激发出每一个电子，所以我们要使用，X，射线，它的能量更高，你可以非常确定,我们可以激发出其中所有的电子。
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And I use the term photon here, and that's because he also concluded that light must be made up of these energy packets, and each packet has that h, that Planck's constant's worth of energy in it, so that's why you have to multiply Planck's constant times the frequency.
我这里用光子这个词,是因为他还总结出光,必须由这些能量包组成，每个能量,包有这个h，普朗克常数代表,里面的能量，所以这就是为什么你们,要用普朗克常数乘以频率。
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So you know that x-rays are higher frequency than UV light, for example, that means it's also higher energy than UV light, and if you think back to our photoelectric effect experiments, do you remember what type of light we were usually using for those? Does anyone remember?
你们知道，X，射线的频率比紫外光高，这意味着，它的能量也比紫外光要高，那么，请大家回想一下我们的光电效应实验，大家还记得当时我们用的是什么光源吗？,有人记得吗？
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